Direct growth of CdTe(1 0 0) epilayers on Si(1 0 0) substrate by hot wall epitaxy

Strong preferential (1 0 0) orientation is observed for the first time in the CdTe thin films directly grown on Si(1 0 0) substrates without any buffer layers. This result is attributed to the fact that the epilayer is grown directly on the hydrogen-terminated Si substrate without any preheating treatment. The crystal qualities of CdTe(1 0 0)/Si(1 0 0) and CdTe(1 1 1)/Si(1 1 1) epilayers obtained at the same growth conditions were compared. Atomic force microscopy observations reveal different surface morphology at the early stages of the crystal growth for CdTe(1 1 1)/Si(1 1 1) and CdTe(1 0 0)/Si(1 0 0) epilayers, implying that they are governed by different growth mechanisms. The nucleation of CdTe(1 0 0)/Si(1 0 0) starts with 3D islands having a dome shape. It is demonstrated that the height and diameter distributions narrow and the aspect ratio decreases with decreasing the growth time. The crystallinity of CdTe(1 0 0)/Si(1 0 0) epilayers is inferior to that of CdTe(1 1 1)/Si(1 1 1) due to a double-domain structure.