A new phenomenon of photoconductive InSb detector under the irradiation of out-band laser
波段外激光辐照光导型InSb探测器的一种新现象

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 T2.35.At T>To,the concentration of thermally-activated carrier increases with temperature,which is proportional to exp（—Eg/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.