激光对硅光电二极管的损伤

研究了受强光辐照的硅光电二极管的热损伤。报道了由1.06微米激光脉冲辐照的硅光电二极管的损伤阈值，辐照时间τ为10^-8~1秒。阈值激光辐照产生可见的微观损伤，并使光响应永久降级。响应度的损失随激光感应加热引起的检波二极管特性的降级而来。时间与波长的依赖关系同处理由高斯激光束辐照的半无限材料的热模型所预言的相符。     

硅PIN光电二极管γ电离脉冲辐射的数值模拟

分析了γ电离脉冲辐射诱发硅PIN光电二极管产生光电流的机理.建立了硅PIN光电二极管的器件物理模型以及γ电离脉冲辐射效应模型;运用MEDICI软件,进行了辐射效应数值模拟计算.得出了γ电离脉冲辐射剂量率在10°～109Gy(Si)/s范围内,诱发硅PIN光电二极管光电流变化的初步规律.对比了辐射效应数值模拟结果与国外相关文献给出的辐照实验结果.

Abstract：

The mechanism of photocurrent of Si PIN photodiode induced by γ ionization pulse radiation is analyzed.The device physics and γ ionization pulse radiation models are established to simulate photocurrent of Si PIN photodiode by MEDICI software.The primary regularity of photocurrent of Si PIN photodiode is concluded by γ ionization pulse radiation with the dose rate of 10~0～10~9 Gy (Si)/s.The Simulation results are in agreement with the experimental results given in correlative literatures.     

飞秒激光诱发硅PIN光电二极管饱和特性的实验研究

实验研究了不同脉冲能量的飞秒激光诱发硅PIN光电二极管瞬态响应信号的特性。发现了探测器响应瞬态响应信号相继出现了三个明显的相位,深入讨论了飞秒激光诱发的高注入载流子在瞬态响应信号演化过程中所起的作用。结果表明,高注入载流子产生的空间电荷屏蔽效应是导致瞬态响应信号呈现三个相位的主要因素,它导致瞬态响应信号的持续时间主要取决于载流子双极扩散的速度。增加飞秒激光的脉冲能量会进一步延长探测器瞬态响应信号的持续时间。因此,飞秒激光会削弱探测器的工作性能,尤其是在高速信号探测中的工作性能。     

皮秒激光辐照硅基PIN光电二极管的瞬态响应信号分析

实验研究了超短脉冲皮秒激光辐照硅基PIN光电二极管的瞬态响应的规律特性,测量了在不同激光能量密度辐照下的脉冲响应信号.分析实验结果表明,随着激光能量密度的增大,器件出现了非线性饱和状态,半高宽从37.2μs到113μs,底宽从181μs到322 μs,脉冲响应信号出现展宽现象,信号的展宽意味着器件的瞬态响应发生了退化,同时对于饱和前后的信号特征量的半高宽和底宽进行了分析,发现无论是绝对增幅还是相对增幅,可以看出饱和后有更为显著的展宽现象,并且主要由于器件饱和后的下降沿出现速度的衰减所致.通过理论分析发现,由于注入的光生载流子浓度变化对双极输运过程造成影响,从而改变其载流子输运过程中的速度,导致器件响应出现退化现象.     

激光对光电探测器的损伤阈值研究

本文研究了1.06μm和0.53μm激光对硅pin光电二极管以及硅雪崩光电管的永久性损伤效应,测出了损伤阈值。实验发现,光电探测器的PN结受到激光热烧伤是造成其永久性损伤的重要因素,损伤阈值的大小与激光波长、脉冲宽度以及光电探测器结构有关。     

XeF（C-A）蓝绿激光对可见光面阵CCD软损伤的实验研究

建立了脉冲激光辐照CCD器件实验平台,采用XeF（C-A）蓝绿激光辐照可见光CCD,获得CCD出现软损伤（局部饱和、全饱和、串扰及致眩）的激光能量密度阈值或量级及对应的CCD图像,用饱和面积法分析了蓝绿激光对CCD的软损伤效应。     

自由光通信中PIN探测器光阈值特性研究

研究自由光通信中PIN探测器在1 064 nm波长下的阈值特性。为了观察PIN光电探测器的激光损伤阈值对光通信的影响,利用Nd:YAG激光器、衰减器、示波器和PIN探测器等仪器模拟无线空间光通信系统。实验以PIN探测器在1 064 nm波段为样本。通过调整衰减器的衰减系数,从而观察探测器达到强光饱和时通信波形的眼图变化,判断探测器是否能够继续通信。通过实验发现:探测器达到深度饱和时,系统通信出现脉宽展宽现象,并出现严重的码间串扰无法满足通信指标。通过实验阈值,建立空间数学模型。观察距离、束散角和辐照夹角对致盲激光器功率的影响。     

辐照对硅光电二极管可靠性影响的研究

本文介绍了辐照对硅光电二极管的辐射效应和损伤机制。比较了γ射线、电子、质子、中子以及重离子辐照后,光电二极管各项特性参数的变化。根据辐照对半导体的作用原理,解释不同辐照引起的变化规律。寻求抗辐射加固方法,改善光电二极管的抗辐射性能。     

皮焦耳光脉冲能量测试

研制了用于测量皮焦尔量级光脉冲的微能量计。系统采用PIN光电二极管完成光电转换,由电荷积分器对光脉冲产生的电荷进行积分,得到与能量成正比的电压,从而实现对光脉冲能量的测量。结果表明,该微能量计的测量精度达1pJ,为微弱能量信号的测量提供了一种理想的解决方案。     

一款低成本硅PIN光电二极管偏置电路的设计及应用

硅PIN光电二极管在微弱光信号检测领域的应用越来越广泛,但其效果会受到偏置电压等因素的影响,稳定性高、纹波系数小的偏置电压对准确获得被测信号来说是必不可少的。设计一款基于TPS61040电压转换芯片的硅PIN光电二极管偏置电路,并将其用于NaI(Tl)晶体的微弱光信号检测,取得了良好的效果。     

超短脉冲激光对无机硅材料的损伤

通过控制作用于材料表面的激光能量和脉冲数量,实验研究了800nm,50fs,1kHz激光作用下融石英玻璃和硅片的破坏机制和损伤规律,计算了材料的损伤阈值与脉冲能量以及脉冲数量的依赖关系,并采用简化的理论模型计算了熔石英玻璃材料的损伤阈值与激光脉宽以及光子能量之间的依赖关系。对这两种无机硅材料在飞秒脉冲作用后的微区结构改变进行了扫描电子显微镜(SEM)测试,研究了其形貌特征。结果表明,硅片是由缺陷中的导带电子作为种子电子引发雪崩电离导致材料损伤,而熔石英玻璃是由多光子电离激发出导带电子引发雪崩电离导致材料损伤。     

飞秒超短脉冲激光对硅太阳能电池的损伤阈值研究

首次采用飞秒超短脉冲激光（35 fs）,研究其对硅太阳能电池的损伤阈值。与相同波长的连续激光对比,飞秒激光的损伤阈值略高。这一结果不同于纳秒或皮秒激光,主要是因为当加热脉冲时间相当或小于电子-声子耦合时间时,非热平衡效应显著,热传导现象不再满足Fourier 定律。在实验中采用了光束整形技术,首次采用强度均匀分布的激光研究损伤阈值。此技术能减小高斯激光中心光强过大造成的实验偏差。     

高功率脉冲对PIN 限幅器的毁伤效应研究

本文针对PIN限幅器在高功率脉冲下的毁伤效应，对PIN限幅器归一化吸收、负载和反射功率与阻抗关系进行了 理论分析，并对高功率脉冲注入下PIN 限幅器的瞬态响应进行了仿真分析，结果表明当输入脉冲上升沿小于5ns，输入功 率大于200mW时，限幅器出现明显的尖峰泄漏现象，并且限幅能力趋于饱和，试验结果也验证了仿真分析结果的有效性。     

Effect of ionizing radiation on second breakdown

Constant current pulses, 5–100 μsec in duration, with amplitude sufficient to cause second breakdown in each pulse, were applied to $\text{p}{}^{\mathrm{+}}\text{-n-n}{}^{\mathrm{+}}$ vertical junction silicon-on-sapphire diodes. The diodes were irradiated on every other pulse by a 20 nsec ionizing radiation pulse from a Nd-glass laser with approximately 4 × 10³ rad. per pulse. In all cases where the density of carriers generated by the ionizing radiation was greater than the impurity doping density of the most lightly doped part of the test diode, the reverse-bias second breakdown delay time was increased as a result of irradiation. There was no evidence of heating due to laser radiation in any of the test devices up to the threshold of laser damage.     

Gigahertz repetition-rate from directly diode-pumped femtosecondCr:LiSAF laser

Gigahertz repetition-rate, fundamental modelocking of a directly diode-pumped femtosecond laser is demonstrated for the first time. Transform-limited pulses of 146 fs duration are produced from a compact Cr:LiSAF laser incorporating a semiconductor saturable absorber mirror and pumped by inexpensive, narrow-stripe red laser diodes     

Infrared absorption and momentum relaxation of free carriers insilicon generated by subpicosecond above band gap radiation

The absorption of infrared radiation in Si of various dopings is investigated after free carriers have been generated by absorption of a subpicosecond laser pulse of above band gap photon energy. A theoretical model is presented which predicts the transmission coefficient for an infrared light pulse through a photogenerated e-h plasma in Si of various surface free carrier densities. Experiments are performed in which the transmission coefficient is measured for a 10.6 μm, ~20 ps laser pulse through a crystalline Si-wafer after it has been irradiated by a 490 fs, 616 nm laser pulse of intensities varying over several orders of magnitude. By fitting the experimental data to the theoretical predictions the imaginary component of the dielectric constant is accurately determined. From the results the free carrier absorption cross sections and the average momentum relaxation times are calculated. The momentum relaxation times in n-doped Si at 10.6 fs are much shorter than that of 26.5 fs observed in intrinsic and p-doped Si     

RF model of flexible microwave single-crystalline silicon nanomembrane PIN diodes on plastic substrate

This paper reports the realization and RF modeling of flexible microwave P-type-Intrinsic-N-type (PIN) diodes using transferrable single-crystalline Si nanomembranes (SiNMs) that are monolithically integrated on low-cost, flexible plastic substrates. With high-energy, high-dose ion implantation and high-temperature annealing before nanomembrane release and transfer process, the parasitic parameters (i.e. resistance, inductance, etc.) are effectively reduced, and the flexible PIN diodes achieve good high-frequency response. With consideration of the flexible device fabrication, structure and layout configuration, a RF model of the microwave single-crystalline Si nanomembrane PIN diodes on plastic substrate is presented. The RF/microwave equivalent circuit model achieves good agreement with the experimental results of the single-crystalline SiNM PIN diodes with different diode areas, and reveals the most influential factors to flexible diode characteristics. The study provides guidelines for properly designing and using single-crystalline SiNMs for flexible RF/microwave diodes and demonstrates the great possibility of flexible monolithic microwave integrated systems.     

230 fs, 25 W pulses from conventional mode-locked laser diodes with saturable absorber created by ion implantation

230 fs, 25 W pulses are obtained from conventional mode-locked AlGaAs laser diodes with highly-reflecting external cavities. Uncoated commercial diodes are used with a region of saturable absorption created by ion implantation. The overall pulse performances are believed to be among the best reported from simple electrically-pumped laser diodes without using additional amplifier sections.<>