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用液相外延技术生长的外延层制备了Pb_(0.76)Sn_(0.24)Te/PbTe背面光照异质结构镶嵌阵列。在85K时,这些二极管的光谱峰值发生在13微米,截止波长在14.2微米。该响应波长被认为是迄今所报导的在接近液氮温度下PbSnTe红外探测器的最长响应波长之一。光谱截止波长,正如所预期的那样,在温度降低时即移向长波,在30K时达到最大值,然而,低于该温度时,光谱响应又重行缩短。这种特性可用禁带宽度、费密能级、光学跃迁的热展宽对温度的关系来说明。
A Pb_ (0.76) Sn_ (0.24) Te / PbTe backside illumination heterostructure mosaic array was prepared by epitaxial layer grown by liquid phase epitaxy. At 85K, the spectral peak of these diodes occurs at 13 microns with a cutoff wavelength of 14.2 microns. This response wavelength is considered to be one of the longest response wavelengths of PbSnTe IR detectors hitherto reported near liquid nitrogen temperature. The spectral cut-off wavelength, as expected, shifts to longwave as the temperature decreases, reaching a maximum at 30K, however, below which the spectral response is shortened again. This property can be described by the bandgap, fermi level, and the thermal spread of the optical transition as a function of temperature.