探索了一种准确测量过冷度的实验方法, 并在此基础上, 利用光学显微镜、傅里叶红外透射光谱仪、台阶仪、白光干涉仪等测试手段分析了过冷度对HgCdTe薄膜厚度均匀性的影响.研究结果表明, 过冷度小于2 ℃, 薄膜容易出现中心凹陷、四周凸起的现象; 过冷度大于3 ℃, 薄膜中心将会明显凸起, 出现宽度为毫米级的周期性起伏, 并伴随有crosshatch线产生.当过冷度为2.5 ℃时, 薄膜厚度极差可缩小至0.5 μm, 0.5 mm×0.5 mm范围内薄膜相对于衬底的粗糙度增加量为9.07 nm.

In this paper, a method to accurately measure the supercooling of HgCdTe films grown by LPE has been proposed. Influences of supercooling on the thickness uniformity of HgCdTe films have been studied by combining with optical Microscope, Fourier transform infrared (FTIR), step profiler and White-light Interferometer (WLI). Results show that, thickness in the center of a 20 mm×25 mm film decreases when supercooling is less than 2℃, while it increases significantly with cross-hatch pattern when supercooling is more than 3℃. Thickness variation of a 20 mm×25 mm film could be less than 0.5 μm, and the surface roughness is comparable with CZT substrate when the supercooling is around 2.5℃.