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本文提出一种制取Cd_xHg_(1-x)Te外延薄膜的新方法。这种方法是在等温条件下把HgTe淀积到真空蒸发CdTe薄膜上。研究了所制薄膜的结构、光、电和光电性能。结构研究结果说明,在晶体衬底(云母、蓝宝石)上的是外延薄膜,而在非晶形衬底上的薄膜是多晶或具有大晶粒的结构。已发现在被有氧化物薄膜的硅上可以进行外延生长。光学研究证明化学组分的横向均匀度(△x/△l<10~(-1)米~(-1))很好。对设定组分的偏离△x不超过0.003。电性能测量结果说明,用该法可以得到具有高或低(n<3×10~(20)米~(-3),在x=0.2时)载流子浓度的p-和n-型层。外延层中的载流子迁移率在300K、x=0.1时高达3.8米~2伏~(-1)秒~(-1)、在77K、x=0.2时超过12米~2伏~(-1)秒~(-1)。最佳薄膜的载流子寿命τ达10~(-6)秒(在295K x=0.26时和77K x=0.2时)。本文所介绍的外延Cd_xHg~(1-x)Te薄膜将用于波长范围2～14微米的光导探测器和8～14微米的光电磁探测器方面。
In this paper, a new method of preparing Cd_xHg_ (1-x) Te epitaxial thin films is proposed. In this method, HgTe is deposited on a vacuum-evaporated CdTe film under isothermal conditions. The structure, optical, electrical and optoelectronic properties of the films were investigated. Structural studies show that epitaxial films are on crystalline substrates (mica, sapphire), whereas films on amorphous substrates are polycrystalline or have large grains. It has been found that epitaxial growth on silicon covered with an oxide film is possible. Optical studies show that the chemical composition of the lateral uniformity (△ x / △ l <10 ~ (-1) m ~ (-1)) is very good. Deviation from the set point Δx does not exceed 0.003. The measurement results of the electrical properties show that p- and n-type layers with high or low carrier concentration (n <3 × 10 ~ (20) m -3, at x = 0.2) can be obtained by this method. . The carrier mobility in the epitaxial layer is as high as 3.8 mV to 2V -1 at 300K and at x = 0.1 and exceeds 12 mV to 2V at 77K and x = 0.2. 1) seconds ~ (-1). The best film has a carrier lifetime τ of 10 -6 seconds (at 295K x = 0.26 and 77K x = 0.2). The epitaxial Cd_xHg ~ (1-x) Te thin films described in this paper will be used in photoconductive detectors with wavelength range of 2 ~ 14μm and 8 ~ 14μm.