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GaAs-based 5-mm-gap photoconductive semiconductor switches (PCSSs), with a thickness of 1 mm, are fabricated. A 60° beveling angle is used to make a periodic array of grooves on the surface of GaAs by mechanical processing. The laser beam should be reflected back when a vertical laser is illuminated on these grooves according to total internal refl...
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Citations
... After the SI-GaAs PCSS enters the nonlinear operating mode, the ON-state resistance of the SI-GaAs PCSS decreases sharply to the ohmic or subohmic order due to the avalanche multiplication effect of carriers [17]. At this time, the switching impedance Z 0 is smaller than Z s , the reflection coefficient ρ < 0 and the reflected voltage V r is negative, according to Equation (5). ...
In this paper, the output electrical pulse width of semi-insulating gallium arsenide photoconductive semiconductor switch (SI-GaAs PCSS) is controlled by means of Blumlein pulse formation line. Under the condition that the bias voltage is 28 kV and the laser pulse width is 9.5 ns, the electric pulse width obtained by using high-power pulse system transmission is 10 ns and the output voltage is 23 kV. Based on the Blumlein pulse formation line theory, the output pulse width and transient impedance are analyzed. The results show that the holding time of carriers avalanche multiplication can be controlled.
... The single PCSS jitter can be calculated by: The semiconductor resistance converged quickly in the proposed configuration, as shown in Figure 8. When the GaAs PCSS operated in the high avalanche mode, the ONstate minimum resistance could reach the sub-Ohm level, achieving the value of 0.58 Ω under the bias voltage of 35 kV, which was lower than the value of 2.14 Ω reported in [26]. where R is the current-limiting resistor value and, in this work, its value is 890 Ω. ...
... The semiconductor resistance converged quickly in the proposed configuration, as shown in Figure 8. When the GaAs PCSS operated in the high avalanche mode, the ONstate minimum resistance could reach the sub-Ohm level, achieving the value of 0.58 Ω under the bias voltage of 35 kV, which was lower than the value of 2.14 Ω reported in [26]. The 10-mm GaAs PCSS charged by a 30-pF capacitor was tested for stability at the bias voltages of 30 kV and 35 kV. ...
In this paper, a three-layer GaAs photoconductive semiconductor switch (GaAs PCSS) is designed to withstand high voltage from 20 to 35 kV. The maximum avalanche gain and minimum on-state resistance of GaAs PCSS are 1385 and 0.58 Ω, respectively, which are the highest values reported to date. Finally, the influence of the bias voltage on the avalanche stability is analyzed. The stability of the GaAs PCSS is evaluated and calculated. The results show that the jitter values at the bias voltages of 30 kV and 35 kV are 164.3 ps and 106.9 ps, respectively. This work provides guidance for the design of semiconductor switches with high voltage and high gain.
... For example, a 532 nm wavelength laser has a penetration depth of only 0.1 µm [9]. Moreover, aportion of this incident light gets reflected from the substrate, resulting in a low light utilization efficiency [14]. This low penetration depth results in relatively small effective volume of PCSS, which limits the on-state resistance, as described by Eq. (4). ...
We report a new, to the best of our knowledge, type of SI-GaAs photoconductive semiconductor switch (PCSS) with nanostructures. Since light can enter from both the top and side surfaces of nanostructures, the effective penetration depth is significantly increased. Lower on-state resistance and a longer lock-on time have been achieved in the nonlinear mode with this design, as well as a lower triggering fluence in the linear mode. This could be highly useful for a variety of applications that require lower on-state resistance and/or longer lock-on time such as pulsed power systems and firing set switches.
With unique characteristics, especially the simultaneous combination of high-power capacity and high repetition frequency, gallium arsenide photoconductive semiconductor switches (GaAs PCSS) have a wide range of applications in the field of pulsed power technology. In view of the ever-shrinking device area and the ever-increasing operating voltage of GaAs PCSS, its sidewall morphology has become more and more obvious on the lifetime and reliability of the device. To address this issue, this article comparatively investigates the influence of GaAs PCSS sidewall morphology on the electrical characteristics of the devices. The results show that the grinding process is favorable to improve the quality of the device sidewalls, so as to achieve the purpose of improving the life and reliability of the device. The leakage current of grinded-GaAs PCSS (G-GaAs PCSS) is reduced to 11.43
$\mu $
A (average value) at a bias voltage of 45 kV, which is more than five times lower than that of the ungrinded-GaAs PCSS (U-GaAs PCSS). Notably, the G-GaAs PCSS enters the nonlinear mode with a lower threshold electric field and a high
$\textit{I}_{\text{light}}$
/
$\textit{I}_{\text{dark}}$
ratio (1.45
$\times$
10
$^{\text{7}}\text{)}$
. The microscopic morphology of the two devices was also experimentally analyzed, and the improvement in the electrical characteristics of the G-GaAs PCSS was attributed to the improvement of the sidewall quality of the device by the grinding process.
In this work, the controllable current diversion based on the inductance modulation has been demonstrated on a two-channel bulk gallium arsenide (GaAs) photoconductive semiconductor switch (PCSS) array. It is found that the additional inductances can regulate the switching speed of each PCSS in the array, then play positive roles in improving the current-sharing effect and sustaining the stability of switching current through the array during consecutive shots. The theory of multiple avalanche domains is introduced to interpret the modulation mechanism by performing a 1-D simulation, and has revealed that the switching speed is essentially determined by the evolution rate of avalanche domains influenced by the dynamic voltage division process, which is modulated by the additional inductances.
To guide the illuminating design to improve the on-state performances of gallium arsenide (GaAs) photoconductive semiconductor switch (PCSS), the effect of spot size on the operation mode of GaAs PCSS based on a semi-insulating wafer with a thickness of 1 mm, triggered by a 1064-nm extrinsic laser beam with the rectangular spot, has been investigated experimentally. It is found that the variation of the spot size in length and width can act on the different parts of the output waveform integrating the characteristics of the linear and nonlinear modes, and then significantly boosts the PCSS toward different operation modes. On this basis, a two-channel model containing the active and passive parts is introduced to interpret the relevant influencing mechanisms. Results indicate that the increased spot length can peak the amplitude of static domains in the active part to enhance the development of the nonlinear switching, while the extended spot width can change the distribution of photogenerated carriers on both parts to facilitate the linear switching and weaken the nonlinear switching, which have been proved by comparing the domain evolutions under different spot sizes.
We demonstrate the positive role of an optical internal reflection structure (OIRS) in improving the on-state performances of gallium arsenide photoconductive semiconductor switch (GaAs PCSS). Herein, the structure consisting of a convex lens and two reflectors creates an effect of increasing the extrinsic absorbance. Under the same laser input, the PCSS employing this structure has achieved higher voltage output, faster switching and lower on-state resistance, which demonstrates at least 1.5-fold improvement in triggering efficiency, compared to the normal device. A two-dimensional (2D) device simulation has been performed and reveals that the positive effect of the OIRS is attributed to the accelerated formation of avalanche domains and the heightened carrier concentration, which are affected by the increased optical absorption.
