Owing to the low p-type doping efficiency in the hole injection layers(HILs)of GaN-based ultra-violet(UV)vertical-cavity surface-emitting laser(VCSEL),effective hole injection in multi-quantum wells(MQW)is not achieve...Owing to the low p-type doping efficiency in the hole injection layers(HILs)of GaN-based ultra-violet(UV)vertical-cavity surface-emitting laser(VCSEL),effective hole injection in multi-quantum wells(MQW)is not achieved,significantly limiting the photoelectric performance of UV VCSELs.We developed a slope-shaped HIL and an EBL structure in AlGaN-based UV VCSELs.In this study,by improving hole in-jection efficiency,the hole concentration in the HIL is increased,and the hole barrier at the electron barrier layer(EBL)/HIL interface is decreased.This minimises the hindering effect of hole injection.A mathematic-al model of this structure was established using a commercial software,photonic integrated circuit simulator in three-dimension(PICS3D).We conducted simulations and theoretical analyses of the band structure and carrier concentration.Introducing polarisation doping through the Al composition gradient in the HIL en-hanced the hole concentration,thereby improving the hole injection efficiency.Furthermore,modifying the EBL eliminated the abrupt potential barrier for holes at the HIL/EBL interface,smoothing the valence band.This improved the stimulated radiative recombination rate in the MQW,increasing the laser power.There-fore,the sloped p-type layer can enhance the optoelectronic performance of UV VCSELs.展开更多
This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system ci...This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system circuit is designed and fabricated,enabling the detection,acquisition,and calibration of weak solar-blind UV signals.Experimental results demonstrate that under zero bias conditions,with a UV light power density of 3.45μW/cm^(2) at 260 nm,the sample achieves a peak responsivity(R)of 0.085 A·W^(−1),an external quantum efficiency(EQE)of 40.7%,and a detectivity(D^(*))of 7.46×10^(12) cm·Hz^(1/2)·W^(−1).The system exhibits a bandpass characteristic within the 240–280 nm wavelength range,coupled with a high signal-to-noise ratio(SNR)of 39.74 dB.展开更多
Research on p-channel field-effect transistors(p-FETs)remains limited,primarily due to the significantly lower conductivity of the two-dimensional hole gas(2DHG)compared to the two-dimensional electron gas(2DEG)in n-c...Research on p-channel field-effect transistors(p-FETs)remains limited,primarily due to the significantly lower conductivity of the two-dimensional hole gas(2DHG)compared to the two-dimensional electron gas(2DEG)in n-channel field-effect transistors(n-FETs),which poses a significant challenge for monolithic integration.In this study,we investigate the impact of epitaxial structure parameters on 2DHG properties in p-Ga N/Al Ga N/Ga N heterostructures through semiconductor technology computer-aided design(TCAD)simulations and theoretical calculations,identifying the conditions necessary to achieve high-density 2DHG.Our simulations demonstrate that increasing the p-Ga N thickness leads to two critical thicknesses determined by surface states and acceptor ionization concentration:one corresponds to the onset of 2DHG formation,and the other to its saturation.Lowering the donor surface state energy level and increasing the acceptor ionization concentration promote 2DHG formation and saturation,although the saturated density remains independent of surface states.Additionally,a higher Al composition enhances intrinsic ionization due to stronger polarization effects,thereby increasing the 2DHG sheet density.Consequently,to achieve high-density 2DHG in p-Ga N/Al Ga N/Ga N heterostructures,it is essential to increase the Al composition,ensure that the p-Ga N thickness exceeds the critical thickness for 2DHG saturation,and maximize the acceptor ionization concentration.This study elucidates the impact of epitaxial structure parameters on 2DHG properties in p-Ga N/Al Ga N/Ga N heterostructures and provides valuable guidance for the optimization of p-FET designs.展开更多
InGaAs光电探测器因其优异的短波红外响应特性、低暗电流和高响应度,在红外成像、激光通信和光谱检测等领域具有广泛应用。光敏元作为探测器的核心结构,其面积大小不仅影响光通量的吸收效率,还关系到器件的空间分辨率和光电性能。然而,...InGaAs光电探测器因其优异的短波红外响应特性、低暗电流和高响应度,在红外成像、激光通信和光谱检测等领域具有广泛应用。光敏元作为探测器的核心结构,其面积大小不仅影响光通量的吸收效率,还关系到器件的空间分辨率和光电性能。然而,光敏元面积对光电流特性的具体影响规律仍需系统实验验证。为此,本文设计并制备了光敏元面积从30 × 30 μm2至500 × 500 μm2的InGaAs探测器样品,测试并分析了其在暗态和光照条件下的电流–电压(I-V)特性。结果表明,随着光敏面积的增加,光电流呈明显增强趋势,且I-V曲线形状保持一致,反映出材料制程的一致性。在暗态下,暗电流随光敏元面积的增大而增大,但单位面积暗电流密度基本稳定,说明其主要来源为体电流。在光照条件下,不同面积器件的光电流接近线性增长,验证了光敏面积对光响应能力的直接影响。研究结果为InGaAs光电探测器在高分辨率与多像元集成应用中的结构设计提供了重要参考。This InGaAs photodetector, with its excellent short-wavelength infrared response, low dark current, and high responsivity, has been widely applied in infrared imaging, laser communication, and spectral detection. As the core structure of the detector, the area of the photosensitive element not only affects the efficiency of light flux absorption but also relates closely to the spatial resolution and photoelectric performance of the device. However, the specific influence of the photosensitive area on photocurrent characteristics still requires systematic experimental verification. To this end, this study designs and fabricates InGaAs detector samples with photosensitive areas ranging from 30 × 30 μm2 to 500 × 500 μm2, and investigates their current-voltage (I-V) characteristics under both dark and illuminated conditions. The results show that as the photosensitive area increases, the photocurrent exhibits a significant rising trend, while the overall I-V curve shape remains consistent, reflecting the uniformity of the material fabrication process. Under dark conditions, the dark current increases with the photosensitive area, but the dark current density per unit area remains nearly constant, indicating that the primary source is bulk current. Under illumination, the photocurrent of devices with different areas increases nearly linearly, confirming the direct impact of the photosensitive area on light response capability. These findings provide valuable reference for structural design in high-resolution and multi-pixel integrated applications of InGaAs photodetectors.展开更多
文摘Owing to the low p-type doping efficiency in the hole injection layers(HILs)of GaN-based ultra-violet(UV)vertical-cavity surface-emitting laser(VCSEL),effective hole injection in multi-quantum wells(MQW)is not achieved,significantly limiting the photoelectric performance of UV VCSELs.We developed a slope-shaped HIL and an EBL structure in AlGaN-based UV VCSELs.In this study,by improving hole in-jection efficiency,the hole concentration in the HIL is increased,and the hole barrier at the electron barrier layer(EBL)/HIL interface is decreased.This minimises the hindering effect of hole injection.A mathematic-al model of this structure was established using a commercial software,photonic integrated circuit simulator in three-dimension(PICS3D).We conducted simulations and theoretical analyses of the band structure and carrier concentration.Introducing polarisation doping through the Al composition gradient in the HIL en-hanced the hole concentration,thereby improving the hole injection efficiency.Furthermore,modifying the EBL eliminated the abrupt potential barrier for holes at the HIL/EBL interface,smoothing the valence band.This improved the stimulated radiative recombination rate in the MQW,increasing the laser power.There-fore,the sloped p-type layer can enhance the optoelectronic performance of UV VCSELs.
基金supported by the Director’s Fund for the‘Climbing Plan’of the National Space Science Centre of the Chinese Academy of Sciences(No.E2PD10011S)the National Engineering Research Centre for Mobile Private Networks Project(No.BJTU20221102).
文摘This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system circuit is designed and fabricated,enabling the detection,acquisition,and calibration of weak solar-blind UV signals.Experimental results demonstrate that under zero bias conditions,with a UV light power density of 3.45μW/cm^(2) at 260 nm,the sample achieves a peak responsivity(R)of 0.085 A·W^(−1),an external quantum efficiency(EQE)of 40.7%,and a detectivity(D^(*))of 7.46×10^(12) cm·Hz^(1/2)·W^(−1).The system exhibits a bandpass characteristic within the 240–280 nm wavelength range,coupled with a high signal-to-noise ratio(SNR)of 39.74 dB.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFB3604203)the Key Research and Development Program of Guangdong Province,China(Grant No.2024B0101060002)the Key Research and Development Program of Shenzhen City,China(Grant No.JCYJ20241202130036043)。
文摘Research on p-channel field-effect transistors(p-FETs)remains limited,primarily due to the significantly lower conductivity of the two-dimensional hole gas(2DHG)compared to the two-dimensional electron gas(2DEG)in n-channel field-effect transistors(n-FETs),which poses a significant challenge for monolithic integration.In this study,we investigate the impact of epitaxial structure parameters on 2DHG properties in p-Ga N/Al Ga N/Ga N heterostructures through semiconductor technology computer-aided design(TCAD)simulations and theoretical calculations,identifying the conditions necessary to achieve high-density 2DHG.Our simulations demonstrate that increasing the p-Ga N thickness leads to two critical thicknesses determined by surface states and acceptor ionization concentration:one corresponds to the onset of 2DHG formation,and the other to its saturation.Lowering the donor surface state energy level and increasing the acceptor ionization concentration promote 2DHG formation and saturation,although the saturated density remains independent of surface states.Additionally,a higher Al composition enhances intrinsic ionization due to stronger polarization effects,thereby increasing the 2DHG sheet density.Consequently,to achieve high-density 2DHG in p-Ga N/Al Ga N/Ga N heterostructures,it is essential to increase the Al composition,ensure that the p-Ga N thickness exceeds the critical thickness for 2DHG saturation,and maximize the acceptor ionization concentration.This study elucidates the impact of epitaxial structure parameters on 2DHG properties in p-Ga N/Al Ga N/Ga N heterostructures and provides valuable guidance for the optimization of p-FET designs.
文摘InGaAs光电探测器因其优异的短波红外响应特性、低暗电流和高响应度,在红外成像、激光通信和光谱检测等领域具有广泛应用。光敏元作为探测器的核心结构,其面积大小不仅影响光通量的吸收效率,还关系到器件的空间分辨率和光电性能。然而,光敏元面积对光电流特性的具体影响规律仍需系统实验验证。为此,本文设计并制备了光敏元面积从30 × 30 μm2至500 × 500 μm2的InGaAs探测器样品,测试并分析了其在暗态和光照条件下的电流–电压(I-V)特性。结果表明,随着光敏面积的增加,光电流呈明显增强趋势,且I-V曲线形状保持一致,反映出材料制程的一致性。在暗态下,暗电流随光敏元面积的增大而增大,但单位面积暗电流密度基本稳定,说明其主要来源为体电流。在光照条件下,不同面积器件的光电流接近线性增长,验证了光敏面积对光响应能力的直接影响。研究结果为InGaAs光电探测器在高分辨率与多像元集成应用中的结构设计提供了重要参考。This InGaAs photodetector, with its excellent short-wavelength infrared response, low dark current, and high responsivity, has been widely applied in infrared imaging, laser communication, and spectral detection. As the core structure of the detector, the area of the photosensitive element not only affects the efficiency of light flux absorption but also relates closely to the spatial resolution and photoelectric performance of the device. However, the specific influence of the photosensitive area on photocurrent characteristics still requires systematic experimental verification. To this end, this study designs and fabricates InGaAs detector samples with photosensitive areas ranging from 30 × 30 μm2 to 500 × 500 μm2, and investigates their current-voltage (I-V) characteristics under both dark and illuminated conditions. The results show that as the photosensitive area increases, the photocurrent exhibits a significant rising trend, while the overall I-V curve shape remains consistent, reflecting the uniformity of the material fabrication process. Under dark conditions, the dark current increases with the photosensitive area, but the dark current density per unit area remains nearly constant, indicating that the primary source is bulk current. Under illumination, the photocurrent of devices with different areas increases nearly linearly, confirming the direct impact of the photosensitive area on light response capability. These findings provide valuable reference for structural design in high-resolution and multi-pixel integrated applications of InGaAs photodetectors.
