It was observed that undoped ZnSe films, which were grown onto GaAs substrates by means of molecular beam epitaxy, exhibited an irregular array of interfacial 60 misfit dislocations. However, N and Cl doping of the ZnSe films altered the interfacial dislocation structure. Samples of p-type ZnSe with N concentrations of about 1018/cm3 exhibited a regular array of interfacial 60 misfit dislocations and a lower (106/cm2) density of threading dislocations, as compared with undoped films. However, samples with doping levels which were higher than 1019/cm3 exhibited a threading dislocation density of about 108/cm2. These differences were explained in terms of Frank partial dislocations, which were observed only in doped ZnSe. The Frank partial dislocations acted as nucleation sites for misfit dislocations. Thus, there were differing mechanisms for the formation of misfit dislocations in doped and undoped films.

L.H.Kuo, L.Salamanca-Riba, J.M.DePuydt, H.Cheng, J.Qiu: Applied Physics Letters, 1993, 63[23], 3197-9