分子束外延InAlSb红外探测器光电性能的温度效应

Temperature effect of InAlSb infrared detectors on photoelectric properties by molecular beam epitaxy

采用分子束外延生长方法在In Sb(100)衬底上生长p^+-p^+-n-n^+势垒型结构的In_(1-x)Al_xSb外延层。运用X射线衍射对材料的晶体质量及Al组分进行测试和表征,In Al Sb外延层的半峰宽为0.05°,表明外延材料的单晶性能良好,并通过布拉格方程和维戈定律计算出Al组分为2.5%。然后将外延材料制备成多元红外探测并测得77~210 K下的光谱响应曲线,实验发现探测器的截止波长从77 K时的4.48μm增加至210 K时的4.95μm。通过数据拟合得出In_(0.975)Al_(0.025)Sb禁带宽度的Varshni关系式以及其参数E_g(0)、α和β的值分别为0.238 6 e V,2.87×10^(-4 )e V/K,166.9 K。经I-V测试发现,在110 K,-0.1 V偏压下,器件的暗电流密度低至1.09×10^(-5 )A/cm^(-2),阻抗为1.40×10~4Ωcm^2,相当于77 K下In Sb探测器的性能。同时分析了温度对器件不同类型的暗电流的影响程度,并得到器件的扩散电流与产生-复合电流的转变温度约为120 K。

The In1-xAlxSb epitaxial layers of p＋-p＋-n-n＋ barrier structure were grown on the InSb（100） substrate by molecular beam epitaxy. The crystal quality and Al composition of the material were measured and characterized by X-ray diffraction. The full width at half maximum of the InAlSb epitaxial layer was 0.05°, indicating good performance monocrystalline epitaxial material. The Al content of 2.5% was calculated according to Bragg＇s formula and Vegard＇s law. When the InAlSb material was fabricated as an infrared detector diode and the spectral response curve was measured at 77 K to 210 K, it was found that the cutoff wavelength of the detector increased from 4.48 μm at 77 K to 4.95 Iμm at 210 K, By fitting the Varshni relation of Ino97,5Al0.025Sb with the experimental data of bandgap, the values of Eg（0）, α and β are 0.238 6 eV, 2.87×10-4eV/K and 166.9 K, respectively. After the I-V test, the dark current density reached as low as 1.09×10-5 A/cm-2 and the resistance area product is 1.40×104Ωcm2 at 110 K, -0.1 V bias, which is equivalent to the influence of the temperature on different types temperature between the diffusion current and G-R performance of InSb detector at 77 K. Besides, the of dark current was analyzed, and the transition current was 120K