【作者】 高绍兵；

【导师】 施卫；

【作者基本信息】 西安理工大学 ， 物理电子学， 2008， 硕士

【摘要】 半导体光导开关(Photoconductive Semiconductor Switches简称PCSS’s)是利用超快脉冲激光器与光电导体(如GaAs,InP等)相结合形成的一类新型器件。光导开关具有优良的电器特性,如上升时间短(几十皮秒量级)、响应速度快、光电隔离好、抗干扰能力强、动态范围宽等特点。在超高速电子学、超宽带雷达、超宽带通讯和瞬态电磁波技术等领域有着广泛的应用前景。本文主要研究了半绝缘GaAs光导开关中EL2本征深施主能级,由于光导开关中EL2能级的存在,使得开关可以吸收比本征吸收限大的激光脉冲;本文分别讨论了光子能量为1.13eV和1.167eV的光照射光导开关时候的吸收机制。对于用1.13eV的光淬灭EL2能级时,表现为光电导先增加到最大值后减小到一极小值后又缓慢增大,最终达到一个饱和值的现象;此现象和半绝缘GaAs中EL2能级中的EL2~0中性能级向亚稳态能级EL2~*的转化、及EL2~+能级有关。而光子能量为1.167eV即1064nm激光脉冲触发光电导开关时有光电导的产生,在1064nm激光脉冲触发下,光导开关可以工作在线性工作模式、非线性工作模式和复合工作模式;在三种工作模式中EL2能级发挥不同的作用,尤其在复合工作模式中的延迟效应,可以利用EL2能级很好的解释这个延迟效应。在GaAs光导开关超短电脉冲响应特性中研究了输出超短电脉冲的上升时间和触发光能之间的关系及其原理分析。本文在讨论上面内容前,先对半绝缘GaAs材料中的本征缺陷EL2能级的结构模型,EL2的亚稳态能级特性,EL2在半绝缘GaAs晶体中的分布和其浓度测量,还有热处理对EL2能级的影响等进行讨论。由于光淬灭实验中所用的材料电参数的热稳定性影响,所以本文中也对半绝缘GaAs的半绝缘特性补偿机制和电参数的热稳定性进行了详细讨论。更多还原

【Abstract】 Photoconductive Semiconductor Switches（PCSS’s）is a new semiconductor device that combines ultra-short laser pulse with photoelectric semiconductor（GaAs,InP and so on）. PCSS’s have the excellent base operating characteristic of electrical apparatus,such as the short rise-time of electromagnetic pulse,fast response speed,wide change of dynamic state,the good ability of optoelectronic isolation and anti-interference.Therefore it is widely used in some field,such as ultra-speed electronics,ultra-band radar,ultra-band communication and the technology of transient electromagnetic wave.The intrinsic donor level deep EL₂ in semiconductor GaAs is investigated in this paper.Based on the EL₂ donor level,the laser pulse which is longer than intrinsic absorption edge can be absorbed.The absorption principle when PCSS’s are exposed by laser in 1.13eV and 1.167eV photon energy.In the condition of 1.13eV photon energy,photo-conductance deduces to a minimum before rises to a maximum,finally, arrives at a saturation value.The phenomenon is connected with the conversion from EL2⁰ neutral energy level to metastable energy level EL2^* and EL2⁺ level in semiconductor GaAs. When the PCSS is irrigated by 1064nm laser,there are three modes,linear mode,nonlinear mode and compound mode.The EL2 energy level plays different roles in three modes. Especially in the compound mode,the EL2 energy level can be well used to explain the late effect.The relationship between rise time of output ultra-short pulse and laser is analyzed in this paper.The structural model of EL2 trap,the characteristic of metastable energy level EL2 the distribution of EL2 in semiconductor GaAs,the measure of density and the affection of heating processing are discussed at the beginning of this paper.Based on the affection of heat endurance of material electrical parameter in the experiment,the heat endurance of electrical parameter and semiconductor character’s compensation principle of semiconductor GaAs are detailed discussed in this paper.更多还原