Defects in ZnSe/ZnTe multiple quantum well-based pseudo-ohmic contacts to p-ZnSe

The microstructure of ZnSe/ZnTe multiple quantum well-based pseudo-ohmic co ntacts to p-ZnSe was investigated using transmission electron microscopy an d high-resolution transmission electron microscopy. In the case of samples consisting of five ZnSe/ZnTe multiple quantum wells, both pure edge Lomer d islocations and 60 degrees dislocations were identified at the interface be tween the ZnSe/ZnTe multiple quantum wells and the ZnTe overlayer, along wi th partial dislocations bounding stacking faults. The dominant dislocations at the interface are Lomer dislocations. In the case of samples grown unde r group II-rich conditions, the interface exhibits corrugations. At the top and bottom of the corrugations, the Lomer dislocations are dominant and in the slope of the corrugations, 60 degrees dislocations are dominant. In th e case of samples grown using migration-enhanced epitaxy, V-shaped defects consisting of three dislocations associated with two stacking faults are fo rmed. The total Burgers vector of the V-shaped defects is a < 100 >. The in creasing total thickness and the number of ZnSe/ZnTe multiple quantum wells leads tend to make the dominant defects dissociated 60 degrees dislocation s. (C) 1999 American Institute of Physics. [S0021-8979(99)00919-6].