波段外激光辐照光导型InSb探测器的一种新现象

利用不同功率密度的10.6 μm(光子能量为0.12 eV)连续激光辐照了禁带宽度为0.228 eV的光导型锑化铟探测器, 得到了与以往报道不同的实验现象. 当10.6 μm波段外激光辐照光导型探测器时, 探测器吸收激光能量后温度升高. 在探测器的温升过程中, 存在一个转变温度T₀. 当探测器的温度T<T₀时, 载流子浓度基本不变, 迁移率随温度的升高呈T^-2.35趋势下降, 引起探测器的电导率减小, 电阻增大, 响应输出电压升高; 当T>T₀时, 热激发载流子浓度随温度的升高呈指数增长, 电阻急剧下降, 超过了载流子迁移率降低对电阻的影响, 响应输出急剧下降. 光电导探测器在较高功率密度波段外激光辐照下的响应特性是载流子的浓度和迁移率在温度影响下相互作用的结果. 这对进一步完善半导体内载流子输运模型提供了实验依据.

A new phenomenon of photoconductive InSb detector under the irradiation of out-band laser

A new phenomenon is observed when a photoconductive InSb detector with 0.228eV band gap is irradiated by 10.6μm laser, whose photon energy is 0.12 eV.The detector is heated by this out-band laser,due to the absorption of laser energy.However,a transformation temperature To exists in this process.When the temperature of the detector,T,is lower than To,the number of carriers remains constant but the conductivity changes because of a change in mobility.The mobility decreases with the increase of temperature and varies as T^2.35.At T>To,the concentration of thermally-activated carrier increases with temperature,which is proportional to exp（—E_g/2k₀T）.As a result,the influence of carrier concentration becomes more and more important.As a result,the output of the detector decreases.In a word,the output voltage of photoconductive detector results from the temperature dependence of mobility and concentration of carriers.This work provides an experimental basis for improving the carrier transport model.