Sources of misfit dislocations in ZnSe/GaAs (001) heterostructures

Abstract

Strain relaxation in low-mismatch ZnSe/GaAs heterostructures is studied by transmission electron microscopy. The early stages of plastic relaxation proceeds by activation of secondary 1/2<011>{133}slip systems, leaving an array of misfit dislocations aligned along <310> directions in the interface. Threading dislocations originate from randomly distributed, highly strained single-or multi-twinned regions in the ZnSe layer, that are probably due to growth accidents. The influence of cross slip on the propagation of threading dislocations is discussed.

In situ analysis of optoelectronic properties of dislocations in ZnO in TEM observations

“…Even though dislocation glide is a thermally activated process, in the present case, it is very likely that most energy for the glide comes from an electron–hole recombination 12 and the thermal component of the glide is relatively minor. Actually, the minimum energy needed for the glide (in the range of 2.1–2.4 eV) is larger than the activation energy for thermal glide of dislocations in ZnSe (about 1 eV 13), and similar dislocation glide due to a recombination‐enhanced effect is observed in TEM 14. Since the estimated energy is smaller than the band gap energy (2.8 eV at 35 K), electrons and holes would be recombined at a defect level associated with the dislocations.…”

Transmission electron microscopyin situinvestigation of dislocation behaviour in semiconductors and the influence of electronic excitation

“…point defect accumulation consistent with a radiation enhanced climb mechanism. This has been described in another paper[16] and will not be discussed further here. Even if the exact nature of this defect is not completely understood, one of the bounding dislocations is identified as a Shockley partial.…”