Single crystal growth under controlled activity of constituent elements of II-VI ternary solid solution semiconductor with Hg as one of the elements

MCT(1-X&GT；Cd_xTe)是一种很有吸引力的10 nm波段红外探测器。最近，除了红外检测器之外，应用已经扩展到广泛的组合物，从用于光通信的1.3微米波长的光电检测器的x=0.70，到作为伽马射线检测器的x=0.90。MCT在整个成分范围内的有效性需要更方便的晶体生长方法，使我们能够生长具有目标成分的均匀单晶。为此，我们采用了一种改进的THM(移动加热法)来生长具有目标成分的均匀单晶。以镉镉单晶为原料，用汞储存室控制汞在碲溶剂中的活度。通过生长实验，证实了生长管的下降速度必须小于3 mm/d，才能生长出均匀的单晶。通过增加P&lt；Hg&gt；或降低T_g，可以生长x大于x=0.60的组份，并在4.2K测量了光致发光光谱，阐明了禁带宽度与组份的关系。

MCT(Hg_<1-X>Cd_XTe) is attractive as an infrared detetor in the 10 mum wavelength region. Recently, in addition to the infrared detector, applications have extended to a wide range of the compositions from x=0.70 for a photodetector at 1.3 mum wavelength for optical fober telecommunication, to x=0.90 as a gamma-ray detector. The usefulness of MCT over the entire composition range requires more convenient crystal growth methods which enable us to grow homogeneous single crystals with a target composition. For this purpose, we adopted a modified THM(Travelling Heater Method) to grow a homogeneous single crystals with a target composition. A CdTe single crystal was used as a feed and Hg reservoir chamber was used to control the Hg activity in Te solvent. From the growth experiments, it was confirmed that lowering speed of the growth tube had to be less than 3 mm/day and homogeneous single crystals were to be grown. Compositions with x higher than x=0.60 can be grown by increasing P_<Hg> or decreasing T_g. PL (photoluminescence spectra) was measured at 4.2 K and composition dependence of the band gap was clarified.