G.-C. Wang

Rensselaer Polytechnic Institute | RPI · Department of Physics, Applied Physics, and Astronomy

Strongly correlated electron materials harbor interesting materials physics, such as high-Tc superconductivity, colossal magnetoresistance, and metal-insulator transition. These physical properties can be greatly influenced by the dimensionality and geometry of the hosting materials and their interaction strengths with underlying substrates. In a c...

Recently, antimony selenide (Sb2Se3) has exhibited an exciting potential for flexible photoelectric applications due to its unique one-dimensional (1D) chain-type crystal structure, low-cost constituents, and superior optoelectronic properties. The 1D structure endows Sb2Se3 with a strong anisotropy in carrier transport and a lasting mechanical def...

Ru has been considered as an alternative metallic candidate for future local interconnects. The 2D reciprocal space map constructed from the azimuthal reflection high-energy electron diffraction patterns reveals that ultrathin Ru(0001) is epitaxially grown on transferred graphene on amorphous SiO2 through quasi-van der Waals interaction. The in-pla...

2D Ruddlesden-Popper (RP) halide perovskites with natural multiple quantum well structures are an ideal platform to integrate into vertical heterostructures, which may introduce plentiful intriguing optoelectronic properties that are not accessible in a single bulk crystal. Here, we report liquid-phase van der Waals epitaxy of a 2D RP hybrid perovs...

The ability to reconfigure spin structure and spin‐photon interactions by an external electric field is a prerequisite for seamless integration of opto‐spintronics into modern electronics. In this work, the use of electric field on the tuning of circular photo galvanic effect in a quasi‐2D oxyhalide perovskite Bi4NbO8Cl is reported. The electrical...

Pyroelectricity describes the generation of electricity by temporal temperature change in polar materials1–3. When free-standing pyroelectric materials approach the 2D crystalline limit, how pyroelectricity behaves remained largely unknown. Here, using three model pyroelectric materials whose bonding characters along the out-of-plane direction vary...

Chemically stable quantum-confined 2D metals are of interest in next-generation nanoscale quantum devices. Bottom-up design and synthesis of such metals could enable the creation of materials with tailored, on-demand, electronic and optical properties for applications that utilize tunable plasmonic coupling, optical nonlinearity, epsilon-near-zero...

There has been increasing interest in the fabrication of thin film materials with mixed dimensions, in particular, 2D to 3D and 3D to 2D heterostructures. Often, if the interface interaction is weak, the lattice matching criterion between the substrate and overlayer can be lifted. If the overlayer lattice is completely relaxed, it can form an incom...

The theoretical Shockley–Queisser limit of photon–electricity conversion in a conventional p–n junction could be potentially overcome by the bulk photovoltaic effect that uniquely occurs in non-centrosymmetric materials. Using strain-gradient engineering, the flexo-photovoltaic effect, that is, the strain-gradient-induced bulk photovoltaic effect,...

Sb2Se3 thin film is an emerging photon absorber used in solar cells. We report the study of surface and interface structures of Sb2Se3(120) film grown on mica substrate by a high-rate vapor transport method. The interface epitaxial relationship between Sb2Se3 and mica examined by the cross- sectional TEM images and diffraction patterns along the [0...

Monolayer WSe2, a 2D transition metal dichalcogenide (TMDCs), has been demonstrated as a good candidate for potential applications in optoelectronics. It is imperative to know the crystalline quality of WSe2 over the wafer scale prior to its applications. Azimuthal reflection high-energy electron diffraction (ARHEED) is demonstrated to be a powerfu...

Chemically stable quantum-confined 2D metals are of interest in next-generation nanoscale quantum devices. Bottom-up design and synthesis of such metals could enable the creation of materials with tailored, on-demand, electronic and optical properties for applications that utilize tunable plasmonic coupling, optical non-linearity, epsilon-near-zero...

Recently, Sb2Se3, an Earth-abundant constituents compound, has emerged as a promising low-cost thin film photovoltaic material. The Sb2Se3 solar cells with a polycrystalline CdS buffer layer suffer from unsatisfactory photoexcitation stability. Herein, we fabricate flexible Sb2Se3 thin film solar cells by utilizing the transferable van der Waals ep...

Molybdenum disulfide (MoS 2 ) on the c -plane sapphire has been a very popular system to study in the two-dimensional (2D) materials community. Bottom-up synthesis of monolayer (ML) MoS 2 with excellent electrical properties has been achieved on sapphire by various methods, making it a very promising candidate to be used in the next generation nano...

Semiconductor thin films grown on weakly interacting substrates have recently attracted much attention due to the fact that one can peel/release the film from its substrate for flexible electronic and optoelectronic applications. In this work we report separable CdTe(1 1 1) epitaxial films grown on mica substrate via vapor transport deposition. The...

V-VI binary chalcogenides, Sb2Se3 has attracted considerable attention for its applications in thin film optoelectronic devices due to its unique 1D structure and remarkable optoelectronic properties. Herein, we report Sb2Se3 thin film epitaxially grown on the flexible mica substrate through the relatively weak (van der Waals) interaction by vapor...

In a metallic multilayer structure, interfacial scattering of carriers reduces the electrical conductance, but carrier localization at the interfaces can have equally significant effects. The authors have grown superlattices consisting of nanometer-thin, alternating Cu and transition metal layers (Cu/Ru, Cu/Co, and Cu/Mo) by magnetron sputtering an...

Most high-quality CdTe thin films are epitaxially grown on single-crystalline substrates through chemical bondings by either molecular beam epitaxy or metalorganic chemical vapor deposition. The epitaxial CdTe films are rarely applied in electronic or optoelectronic devices because of the rigid single-crystalline substrate. We present high-quality...

Single crystal graphite is an extremely useful substrate to grow functional single crystalline films for future electronic and optoelectronic device applications. Due to the weak van der Waals force, it allows one to grow high quality epitaxial films without the restriction of lattice matching and the films are relaxed at the interface without gene...

It is well-known that the electrical conductivity of a metallic film reduces dramatically when the film becomes very thin. This effect is mainly attributed to surface scattering of the conducting carriers. In a multilayer structure, interface scattering also reduces the conductance, but chemical reactions at the interfaces can have equal or bigger...

Atmospheric pressure chemical vapor deposition (APCVD) is employed for the synthesis of layered vanadium disulfide. By tuning several critical growth parameters, we achieve VS2 flakes with lateral dimension over 100 μm and thickness down to monolayer (~0.59 nm) and bilayer (~1.17 nm), larger and thinner than those previously reported in the literat...

Unlike the vast majority of transition metal dichalcogenides which are semiconductors, vanadium disulfide is metallic and conductive. This makes it particularly promising as an electrode material in lithium-ion batteries. However, vanadium disulfide exhibits poor stability due to large Peierls distortion during cycling. Here we report that vanadium...

We present the magnetic properties of three-bilayer superlattices [Co(0.8 nm)/Cu(1.1 nm)] 3 and Co(0.8 nm)/Al(2.2 nm)] 3 grown by magnetron sputter deposition on SiO 2 substrates. Using the surface magneto-optical Kerr effect we observed longitudinal magnetic hysteresis loops with low coercivity values of <17 × 10 ⁻⁴ T and <7 × 10 ⁻⁴ T from Co/Cu a...

Many diffraction and imaging techniques have been developed and used to measure the strains in epitaxial films with different degrees of accuracy. In this tutorial, we will focus on measurements of strains in epitaxial films using electron diffraction techniques. These include reflection high-energy electron diffraction (RHEED), azimuthal reflectio...

We present a simple method of variable temperature process that can potentially enhance the hydrogen storage properties of a large variety of solid state materials. In this approach, hydrogen gas is first introduced at about room temperature, which is followed by a gradual increase to a preset maximum temperature value, Tmax. Using this approach, w...

Traditionally, a high-quality CdTe film can only be grown on a single crystal substrate with a small lattice mismatch. Herein, we report the epitaxy of CdTe films on monolayer single crystal graphene buffered amorphous SiO2/Si(100) substrates, despite a 86% lattice mismatch between CdTe(111) and graphene. X-ray pole figure, electron backscatter dif...

High quality heteroepitaxy of CdTe is challenging due to lattice mismatches of CdTe with many substrates. Herein, we demonstrate the epitaxial growth of single crystalline CdTe films, in multilevel island format, on mica using metalorganic chemical vapor deposition, regardless of large in-plane lattice mismatch (∼13%) between CdTe(111) and mica(001...

ZnTe has a favorable band alignment with CdTe and is an ideal buffer between CdTe and metal contacts used in photovoltaics. Using metalorganic chemical vapor deposition, we report epitaxial growth of ZnTe thin films on 2D substrates, namely, single crystal graphene on amorphous SiO2/Si and freshly cleaved mica(001). Despite the large in-plane latti...

Despite their weak nature, van der Waals (vdW) interactions have been shown to effectively control the optoelectronic and vibrational properties of layered materials. However, how vdW effects exist in Ruddlesden-Popper layered halide perovskites remains unclear. Here we reveal the role of interlayer vdW force in Ruddlesden-Popper perovskite in regu...

In this work, we show that remote heteroepitaxy can be achieved when Cu thin film is grown on single crystal, monolayer graphene buffered sapphire(0001) substrate via a thermal evaporation process. X-ray diffraction and electron backscatter diffraction data show that the epitaxy process forms a prevailing Cu crystal domain, which is remotely regist...

Antimony (Sb) nanostructures, including islands, sheets, and thin films, of high crystallinity were epitaxially grown on single-crystalline graphene through van der Waals interactions. Two types of graphene substrates grown by chemical vapor deposition (CVD) were used, the as-grown graphene on Cu(111)/c-sapphire and the transferred graphene on SiO2...

A multi-step diffusion-mediated process was developed to control the nucleation density, size and lateral growth rate of WSe2 domains on c-plane sapphire for the epitaxial growth of large area monolayer films by gas source chemical vapor deposition (CVD). The process consists of an initial nucleation step followed by an annealing period in H2Se to...

To date, many materials have been successfully grown on substrates through van der Waals epitaxy without adhering to the constraint of lattice matching as is required for traditional chemical epitaxy. However, for elemental semiconductors such as Ge, this has been challenging and therefore it has not been achieved thus far. In this paper, we report...

Conventional hetero-epitaxial films are typically grown on lattice and symmetry matched single crystal substrates. We demonstrated the epitaxial growth of orthorhombic SnS film (∼500 nm thick) on single crystal, monolayer graphene that was transferred on the amorphous SiO2/Si substrate. Using X-ray pole figure analysis we examined the structure, qu...

A two-step process for synthesizing stable Cs2SnI6 perovskite thin films is reported in this letter. The two-step process includes the co-evaporation of two precursors SnI2 and CsI onto a glass substrate, followed by a post thermal annealing process in iodine vapor. Using this technique, pure Cs2SnI6 perovskite thin films were successfully synthesi...

Vanadium dioxide (VO2) and vanadium pentoxide (V2O5) thin films change their properties in response to external stimuli such as photons, temperature, electric field and magnetic field and have applications in electronics, optical devices, and sensors. Due to the multiple valence states of V and non-stoichiometry in thin films it is challenging to g...

Single crystal CdTe films are desirable for optoelectronic device applications. An important strategy of creating films with high crystallinity is through epitaxial growth on a proper single crystal substrate. We report the metalorganic chemical vapor deposition of epitaxial CdTe films on the CdS/mica substrate. The epitaxial CdS film was grown on...

One-dimensional nanoscale epitaxial arrays serve as a great model in studying fundamental physics and for emerging applications. With an increasing focus laid on the Cs-based inorganic halide perovskite out of its outstanding material stability, we have applied vapor phase epitaxy to grow well aligned horizontal CsPbX 3 (X: Cl, Br, or I or their mi...

Knowledge on the symmetry and perfection of a 2D material deposited or transferred to a surface is very important and valuable. We demonstrate a method to map the reciprocal space structure of 2D materials using reflection high energy diffraction (RHEED). RHEED from a 2D material gives rise to 'streaks' patterns. It is shown that from these streaks...

Enhanced van der Waals (vdW) epitaxy of semiconductors on layered vdW substrate is identified as the formation of dative bonds. For example, despite that NbSe2 is a vdW layered material, first-principles calculations reveal that the bond strength at CdTe-NbSe2 interface is five times as large as that of vdW interaction at CdTe-graphene interface. T...

van der Waals epitaxy (vdWE) facilitates the epitaxial growth of materials having a large lattice mismatch with the substrate. Although vdWE of two-dimensional (2D) materials on 2D materials have been extensively studied, the vdWE for three-dimensional (3D) materials on 2D substrates remains a challenge. It is perceived that a 2D substrate passes l...

The effect of CdCl2 heat treatment on the ZnTe layer used as the back electron reflector layer in polycrystalline CdTe solar cells was investigated. A thin film of ZnTe was grown on top of polycrystalline CdTe layer using metalorganic vapor phase epitaxy, which was then subjected to CdCl2 heat treatment. The effect was examined using various charac...

Epitaxial Ge films are useful as a substrate for high-efficiency solar cell applications. It is possible to grow epitaxial Ge films on low cost, cube textured Ni(001) sheets using CaF 2 (001) as a buffer layer. Transmission electron microscopy (TEM) analysis indicates that the CaF 2 (001) lattice has a 45 o in-plane rotation relative to the Ni(001)...

Novel materials suitable for optoelectronics are of great interest due to limited and diminishing energy resources and the movement towards a green earth. We report a simple film growth method to tune the S composition, x from 1 to 2 in semiconductor ultrathin SnSx films on quartz substrates, i.e. single phase SnS, single phase SnS2, and mixed phas...

Realizing high-quality heteroepitaxy of a wide variety of films of very large lattice misfit, f ≥ 10%, with the substrate is a great challenge, but also a potential advancement, because the films may be made threading-dislocation-free as all the dislocations will be confined at the interface. In spite of the numerous experimental findings in the li...

Ge1-xSnx films were grown via physical vapor deposition below the crystallization temperature of Ge on single crystal (111) and (100) CaF2 substrates to assess the role of Sn alloying in Ge crystallization. By studying samples grown at several growth temperatures ranging from 250 oC to 400 oC we report temperature-dependent trends in several of the...

Cube-textured Ni(001) foils have been considered as a viable alternative substrate to grow high quality functional films for large area optoelectronic devices. In this work, we report the heteroepitaxial growth of CaF2(001) films on cube-textured Ni(001) foils at 350-600 oC with in-plane orientation of CaF2[110]//Ni[100] and CaF2[ ]//Ni[010] with 4...

Remarkable properties of layered metal dichalcogenides and their potential applications in various fields have raised intense interest worldwide. We report tens of microns-sized ultrathin single crystal SnS2 flakes grown on amorphous substrates using a simple one-step thermal coevaporation process. X-ray pole figure analysis reveals that a majority...

Heteroepitaxial CdTe films were grown by metal organic chemical vapor deposition on glass substrates through nanostructured Ge/CaF2 buffer layers which were biaxially oriented. It allows us to explore the structural properties of multilayer biaxial semiconductor films which possess small angle grain boundaries and to test the principle of a solar c...

Ultrathin NbS2 films were synthesized from sputter-deposited ultrathin Nb films on SiO2/Si and quartz substrates at 850 °C under sulfur vapor pressure. The structure and surface composition of the synthesized films were characterized by grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. The films have rhombohedral 3R-NbS2 str...

We report two different CdTe homojunction solar cell structures. Single-crystal CdTe homojunction solar cells were grown on GaAs single-crystal substrates by metalorganic chemical vapor deposition. Arsenic and iodine were used as dopants for p-type and n-type CdTe, respectively. Another homojunction solar cell structure was fabricated by growing n-...

A simple method for the synthesis of Nb2O5 films of thicknesses ranging from tens to several hundreds of nanometers on amorphous silicon dioxide or quartz substrates is presented. Nb2O5 films were formed by annealing the sputter deposited Nb films under Ar flow and without oxygen plasma in a quartz tube within a furnace at 850 oC. The structural, c...

The knowledge on the influence of surface roughness and the electron–phonon (el–ph) interaction on electrical transport properties of nanoscale metal films is important from both fundamental and technological points of view. Here we report a study of the temperature dependent electron transport properties of nanoscale copper films by measuring temp...

In this chapter, laboratory x-ray generation, the x-ray area detector, texture classification, and the x-ray pole figure are described. Data collection for x-ray pole figures using a finite size x-ray area detector and the integration steps to construct x-ray pole figures are covered. The chapter serves as a background for RHEED pole figure constru...

In this chapter, kinematic scattering from electrons in atoms arranged in periodic cubic lattices is described. The Laue diffraction conditions in the reciprocal space lattice are derived based on wave interference from periodic lattices. Ewald sphere construction and its interception with a reciprocal lattice are presented to illustrate the requir...

In the last chapter, we presented the principles of x-ray diffraction and the construction of a pole figure, particularly the pole figure constructed from the diffraction patterns obtained by an area detector. In this chapter, we describe the similarities and differences between reflection high-energy electron diffraction (RHEED) transmission mode...

In the last chapter, we discussed some possible origins of texture formation during growth, in particular, the selection of out-of-plane and in-plane crystal orientations when the flux is obliquely incident to the substrate. The exact angle of orientation depends on the incident flux angle. It has been shown that texture orientation as well as the...

Before we discuss analysis of film textures by the x-ray pole figure and reflection high-energy electron diffraction (RHEED) pole figure (transmission mode) techniques, we present in this chapter a more familiar use of RHEED, the reflection mode. This technique has been used extensively for the determination of surface structure and for studies of...

Chapters 6, 7, and 9 ilnclude many examples of using the reflection high-electron energy diffraction (RHEED) pole figure technique for film-texture analysis. Since electrons interact strongly with matter, RHEED is most suitable for the study of texture when there is a limited amount of sample material. This is the case at the initial stages of the...

As we discussed in Chaps. 5 and 6, texture is divided into several classes: single crystal, biaxial, fiber, and random polycrystalline structures. The mechanisms that lead to these different textures are rather complex. They depend on the nature of the substrate (for example, crystalline vs amorphous), substrate temperature, deposition rate, flux e...

In this chapter, we describe the major reflection high-energy electron diffraction (RHEED) hardware components: a vacuum system, an electron gun, a sample manipulator, a step motor, a phosphor screen, and a charge-coupled device camera. Most molecular beam epitaxy (MBE) laboratories with in situ RHEED characterization capability are equipped with t...

Amorphous CdS/single-crystal CdTe solar cells were grown on GaAs substrates by metalorganic chemical vapor deposition. The structures of the films and the electrical properties of the devices were characterized. Highly conducting arsenic-doped ZnTe was grown on GaAs(100) substrates as the buffer layer for CdTe growth. By use of a ∼30-nm ZnTe buffer...

Ge1-xSnx alloyed films were grown on glass substrates by sequential physical vapor deposition of a biaxial CaF2 buffer layer and a Sn heteroepitaxial layer at room temperature, followed by a Ge layer grown at low temperatures (200 - 350 oC). The predeposited Sn on the CaF2 layer enhances the Ge diffusion and crystallization. The Sn substitutes into...

The texture orientation of 2.5, 5, and 100 nm thick Mo films grown by sputter deposition on SiO2 membranes at room temperature has been studied quantitatively using transmission electron microscopy. The sample tilt angle dependent diffraction patterns of these films revealed a fiber texture with the [110] out-of-plane direction for all film thickne...

For any given potential, linear response theory tells us the size that the von Weizsacker coefficient must assume in order to obtain the correct energy in the weak coupling limit. With this necessarily imposed choice, the quality of results is investigated as the coupling is strengthened. From the study of a number of model problems (the harmonic o...

Keywords: Reflection high energy electron diffraction RHEED pole figure Instrument response of transmitted electrons Epitaxial CdTe film Textured CdTe film a b s t r a c t Reflection high-energy electron diffraction (RHEED) pole figure technique using the transmission mode has been developed to study the texture evolution of thin films. For quantit...

This unique book covers the fundamental principle of electron diffraction, basic instrumentation of RHEED, definitions of textures in thin films and nanostructures, mechanisms and control of texture formation, and examples of RHEED transmission mode measurements of texture and texture evolution of thin films and nanostructures. Also presented is a...

The century old oblique angle deposition (OAD) of porous films has received renewed attention recently. The technique can tailor not only the morphology, but also the texture of nanostructures. Nanostructures with a variety of morphologies and textures can be achieved by engineering the incident flux angle, substrate rotation speed, and rotation ax...

In this chapter, the basic unit vectors in real space and the basic unit vectors in reciprocal space, as well as their reciprocal relationships, are described. The commonly used Bravais lattices are summarized. The direction, plane, and interplanar spacing in a real space lattice are defined. The wavevectors, momentum change, Bragg condition, Mille...

Electron phonon (el-ph) coupling is a fundamental quantity that controls the electron transport through a conductor. We experimentally determined the el-ph coupling strength of epitaxial copper (Cu) films ranging from 5 to 1000 nm thick using both ultra-fast, optical pump-probe reflectivity and temperature-dependent resistivity measurements. An enh...

Using a dynamic oblique angle deposition in a flipping rotation mode where the flux incident angle continuously changes during the magnetron sputter deposition, we demonstrated that a stable, biaxial (110)[110] body center cubic (alpha-phase) tungsten nanorod film can be grown on amorphous substrates. In contrast, we showed that only a fiber-textur...

Using dynamic oblique angle deposition with substrate rotation, we showed that single crystal porous Cu(100) films in the form of spirals with an arm diameter ranging from 20 to 50 nm and a spiral diameter ranging from 100 to 150 nm can be epitaxially grown on hydrogen terminated single crystal Si(100) substrate. The epitaxial relationships are (10...

Catalyst Pd decorated Mg nanoblades grown by oblique angle vapor deposition has been shown to possess low desorption temperature and fast kinetics in the dehydrogenation process. Using chemical vapor deposition, we coated these Pd/Mg nanoblades with a shell of ultrathin Parylene N layer that allows high permeation of hydrogen but low permeation of...

Using dynamic oblique angle deposition with substrate rotation, we showed that single crystal porous Cu(100) films in the form of spirals with an arm diameter ranging from 20 to 50 nm and a spiral diameter ranging from 100 to 150 nm can be epitaxially grown on hydrogen terminated single crystal Si(100) substrate. The epitaxial relationships are (10...

We report room temperature measurements of current vs. voltage (I–V) from self-assembled Fe porphyrin [Fe(III) 5,15-di[4-(s-acetylthio)phenyl]-10,20-diphenyl porphine] molecular layers formed on annealed gold crystal facets on glass substrates. I–V curves were measured using an atomic force microscope with a conductive platinum tip. We observed a r...

We have developed a versatile layer-by-layer (LbL) fabrication method to assemble porphyrin based multilayer thin-films on electron-beam evaporated Au surfaces utilizing copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) as both a means of anchoring the films to the Au surface and coupling the individual molecular layers together. The molecular...

Molybdenum films were observed to undergo a dramatic change in crystal texture orientation when the incident flux angle was varied in an oblique angle sputter deposition on amorphous substrates. Reflection high-energy electron diffraction pole figure and scanning electron microscopy were used to analyze in detail the texture orientation of the film...

Quantized conductance measured from single tetraphenylporphyrin molecules with and without a central zinc(II) [Zn(II)] atom was measured using a molecular break junction (MBJ) method. From the conductance histo-grams we observed an additional 1.7 Å stretch for two-state conductance in a single Zn(II) tetraphenylporphyrin (ZnTPP) molecule as compare...

Quasi-single crystal Ge films were grown on cube textured Ni substrate at a temperature of 350 °C using an insulating buffer layer of CaF2. A direct deposition of Ge on Ni at 350 °C was shown to alloy with Ni. From x-ray pole figure analysis, it was shown that Ge grew epitaxially with the same orientation as CaF2 and the dispersions in the out-of-p...

Single crystal-like CdTe thin film has been grown by metalorganic chemical vapor deposition on cube-tex- tured Ni(100) substrate. Using X-ray pole figure measurements we observed the epitaxial relationship of 111CdTe//001Ni with [1P 10]CdTe//[010]Ni and [11P 2] CdTe//[100]Ni. The 12 diffraction peaks in the (111) pole figure of CdTe film and their...

Interface roughness is one of the central features in many important thin film technologies. Roughness is a result of far from equilibrium dynamic growth process and is difficult to describe using conventional statistical mechanics. Recently a dynamic scaling hypothesis has been proposed to describe such a system in which both time and space scalin...

We demonstrated that Pd-decorated Mg blades are air-stable for hydrogen storage with a low desorption temperature of 373 K. Pd-catalyst-decorated Mg blades were prepared by 64° oblique incident angle thermal deposition on a rotatable substrate with the rotation axis perpendicular to the substrate. The hydrogen desorption from Pd-decorated Mg blades...

A class of nanostructured Mo thin films was grown by DC magnetron sputtering using a robust substrate rotation mode called 'flipping rotation'. In this rotation mode, the substrate is arranged to rotate continuously at a fixed speed around an axis lying within and parallel to the substrate. The incident flux is perpendicular to the rotational axis,...

Biaxial crystalline Mg nanoblades were grown by oblique angle thermal evaporation followed by Pd deposition in a vacuum. The hydrogenation-dehydrogenation cycles of Pd-decorated Mg nanoblades was investigated in situ by temperature programmed desorption (TPD). It shows that hydrogen starts desorption at about 340 K and peaks around 373 ± 10 K. If t...

The morphology and texture of Ge films grown under oblique angle vapor deposition on native oxide covered Si(001) substrates at temperatures ranging from 230 °C to 400 °C were studied using scanning electron microscopy, X-ray diffraction and X-ray pole figure techniques. A transition from polycrystalline to {001}<110> biaxial texture was observed w...

The interfacial adhesion energy between metal and porous low-k dielectrics is an important parameter for the reliability study of back-end of line integration. In this work, we have observed the spontaneous film delamination with telephone cord morphology after 130nm thick Ta was sputtered onto methyl silsesquioxane (MSQ) low-k dielectric. The high...

A mechanical vibration system was made by sandwiching an array of parylene-C microsprings between two flat plates of Si. This system was driven mechanically in forced oscillation using a piezo transducer attached to the bottom Si plate. An atomic force microscope was used to record the displacement of the top plate in both the contact and non-conta...

The characteristics of nucleation and island growth in oblique angle deposition with substrate rotation have recently attracted interest due to the formation of novel 3D nanostructures by a physical self-assembly process. In this study, we present the results of a solid-on-solid growth simulation by a kinetic Monte Carlo algorithm that explores the...