GaAs (001) 기판위에 분자선 에피텍시 방법으로 성장시킨 CdxZn1-x Te 에피층에서의 CuPt형 규칙상에 대한 고찰

Abstract

We have studied an atomic ordering and ordered domains in CdxZn1-xTe epilayers grown by molecular beam epitaxy on ZnTe buffer layers. The composition of CdxZn1-xTe thin films was determined by X-ray diffraction patterns using the Vegard’s law. Selected area electron diffraction pattern and high-resolution transmission electron microscopy measurements were performed in order to investigate the ordered structure and ordered domains in CdxZn1-xTe thin films. The strong contrast modulations along the [001] direction parallel to the growth direction were observed in samples with composition x = 0.15~0.76. A superstructure reflection spots corresponding to a CuPt-type ordering were observed. Ordered domain regions were randomly distributed in CdxZn1-xTe thin films. A possible atomic arrangement of and a formation mechanism for the CuPt-type ordered structure in the CdxZn1-xTe epitaxial layer are presented based on the TEM results. These results provide important information on the microstructural properties for enhancing efficiencies of the devices operating at the blue-green region of the spectrum.