Infrared absorption behavior in CdZnTe substrates
Infrared absorption behavior in CdZnTe substrates
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DOI：
10.1007/bf02665843
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发表时间：
2001-06
影响因子：
2.1
通讯作者：
S. Sen;D. Rhiger;C. Curtis;M. H. Kalisher;H. L. Hettich;M. Currie
中科院分区：
文献类型：
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作者：
S. Sen;D. Rhiger;C. Curtis;M. H. Kalisher;H. L. Hettich;M. Currie
抛光CdZnTe晶片的红外（IR）光学透射测量可以提供关于过量杂质、化学计量和不均匀性（沉淀物和夹杂物）的有用信息。研究了室温下Cd_（0.96）Zn_（0.04）Te在8 ~ 20 μ m波段的红外透过行为。测量之前和之后的热处理，涉及控制的镉和锌的超压，这有助于尽量减少镉（阳离子）空位人口。我们的结果支持詹森的极性光学声子散射理论，根据该理论，施主主导的CdZnTe的吸收随m=3而变化.对于受主为主的材料，我们表明，理论吸收的价带间跃迁可以近似由一个类似的幂律与指数m=1，和Cd空位为主的晶片是在合理的协议。我们发现一些晶片中的生长条件表现出部分补偿的杂质施主镉空位受体，并证明去除的补偿退火，以填补空缺。在一个单独的组的晶片，我们发现，所观察到的增加吸收发生在生长过程中的HgCdTe层的液相外延可以解释在镉空位的增加所造成的扩散的Cd到Te沉淀物。这种效应可以通过在Cd-Zn蒸气中退火来逆转，这会填充空位并消除一些沉淀物。通过辉光放电质谱法（GDMS）测量杂质浓度。
Infrared (IR) optical transmission measurements of polished CdZnTe wafers can provide useful information about excess impurities, stoichiometry, and inhomogeneities (precipitates and inclusions). We have investigated the IR transmission behavior of Cd0.96Zn0.04Te between 8 m and 20 m at room temperature. The measurements were made before and after thermal treatments involving control of the Cd and Zn overpressures, which served to minimize the Cd (cation) vacancy population. Our results support the polar optical phonon scattering theory of Jensen, according to which the absorption in donor dominated CdZnTe varies asmwith m=3. For material dominated by acceptors, we show that the theoretical absorption by inter-valence band transitions can be approximated by a similar power law with exponent m=1, and that Cd-vacancy dominated wafers are in reasonable agreement with this. We find some wafers in which the asgrown condition exhibits partial compensation of impurity donors by Cd vacancy acceptors, and demonstrate removal of the compensation by annealing to fill the vacancies. In a separate group of wafers, we find that an observed increase in absorption occurring during growth of a HgCdTe layer by liquid phase epitaxy can be explained in terms of an increase in Cd vacancies caused by diffusion of Cd to Te precipitates. This effect can be reversed by annealing in Cd−Zn vapor, which fills vacancies and eliminates some precipitates. Impurity concentrations were measured by glow discharge mass spectrometry (GDMS).