Yung-Chun Tu's research while affiliated with National Cheng Kung University and other places

... The most efficient and durable light sources are lightemitting diodes [1][2][3]. Numerous studies [4][5][6][7][8][9], performed in the recent decade in the field of creating new semiconductor light-emitting structures, allowed to bring the efficiency of their separate experimental samples to the theoretical limit of light efficiency of artificial light sources [10]. Due to the high reliability and efficiency of modern organic [11][12][13] and inorganic [14][15][16] LEDs, they are widely used, in addition to illumination, in the constructions of displays [18], information boards [19] and indicators [20], providing unattainable for other technologies values of brightness, contrast and energy efficiency. ...

... interface-state defects at the channel/electrode interface should be minimized to increase the height control 18 . The width determined by carrier density (n c ) of the channel material can be narrowed by several approaches [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] . Increasing n c is the simplest method to reduce barrier width, which was originally devised for the Si MOSFETs, and can be realized through ion implantation and/or plasma treatments using elements such as boron, fluorine, argon, or hydrogen [19][20][21]29,30 . ...

... The p-type ohmic contact electrodes of FCLEDs should have high reflectivity and low contact resistance. To realize this, metallic and DBR mirrors can be used as highly reflective layers in flip chips owing to their high reflectance in the visible wavelength range [23]. Further, ITO was sandwiched between the reflection layer and the p-GaN to decrease the p-type contact resistance. ...

... The main advantage of crystalline silicon-based solar cells is the stability of the output power compared to other solar cells, the simplicity of the fabrication process, and the availability of the silicon semiconductor material [1,2]. On the other hand, the indirect bandgap of the crystalline silicon reduces the recombination rate, where the recombination process occurs by creating phonons and photons. ...

... Until now, it has been synthesized by a wide variety of chemical and physical techniques, such as chemical vapor deposition [8], pulsed laser deposition [9], molecular beam epitaxy [10], and the hydrothermal method [11]. Due to the low cost, controlled shape, and large-area compatibility, the hydrothermal method is extremely suitable for the fabrication of high-quality ZnO NRs [12,13]. In terms of applications, ZnO NRs have, until characteristics. ...

... To effectively use the light emitted from the front of the emitting layer, the inverted LED chip has its light-emitting surface on the sapphire side, requiring a reflective layer to be prepared on the front side [8] . Typically, a Ni/Ag/Au composite electrode metal reflector is used, which has serious light absorption and complex process, with reflectivity below 90% in the blue wavelength range. ...

... GaN nanostructures are attractive for various energy applications such as light-emitting diodes (LEDs), laser diodes, solar cells and photocatalysts in chemical hydrogen production due to their excellent optoelectronic properties and stability in harsh environments. [1][2][3][4][5][6][7] Recently, the growth of one-dimensional (1D) GaN nanostructures on metal substrates has attracted special attention due to their direct back contact, high optical reflectivity and good thermal and electrical conductivities, which are limited with conventional substrates such as sapphire and silicon. [8][9][10] Few reports in the literature have presented the growth of 1D GaN nanostructures on various metal substrates. ...

... Hence low cost ethanol sensor without the elevated operating temperature is of superior importance to achieve portability. 5 Hence, research is being carried out to enhance the sensing characteristics of these MOS at room temperature by mastering the morphology and the structure of sensing materials. This is further accomplished by reducing the grain size, doping the metals, loading noble metals, synthesizing novel composite materials and so on. ...

... Surface roughening through the chemical wet etching process [1,2], nanoimprint lithography [3], and nanostructures [4,5] has been applied to roughen the top surface of optoelectronic devices. Surface roughening has attracted considerable interest for applications such as solar cells (SCs), light-emitting diodes (LEDs), ultraviolet photodetectors (UV-PDs), and gas sensors [6][7][8][9]. A suitably roughened surface can significantly improve the surface reflectivity of SCs, alleviate the total internal reflection of LEDs, and increase the responses of UV-PDs and gas sensors [6][7][8][9]. ...

... Heterojunction diodes based on n-ZnO/p-SnO x structure have been explored by researchers [20]- [23], but an n-ZnO/ p-SnO x -based photovoltaic device has not yet been reported. Such a solar cell is expected to be scalable, stable, and nontoxic, while also allowing low-temperature processing, making it an attractive prospect. ...