Electrically stable p-type doping of ZnSe grown by molecular beam epitaxy with different nitrogen activators

Nitrogen doping of ZnSe MBE layers is studied using two original nitrogen a ctivators which controllably produce output beams with different partial co ntent of an atomic nitrogen (N) and metastable electronically excited molec ules (N-2*). The most electrically stable doping with a net acceptor concen tration up to 5 x 10(17) cm(-3) is achieved by an RF capacitively coupled m agnetron activator in the regimes corresponding to maximal partial concentr ation of N-2* while a dominance of N, typical for DC discharge with a vacuu m anode sheath, results in the electrical instability of the doping paramet ers. Low-temperature photoluminescence spectra reveal DAP bands related to shallow and deep donor levels, where the intensities strongly depend on the partial composition of the activator output beam. The results demonstrate that N-2*selective dissociative adsorption at a Zn atom is a favourable p-t ype doping beam. The results demonstrate atomic nitrogen, although providin g a similar net acceptor concentration, appears to be responsible also for the unstable atomic nitrogen, although providing a similar net acceptor con centration, appears to be responsible also for the unstable shallow donor c enter. A (100) split interstitial complex is considered as the most probabl e candidate for this donor. (C) 2000 Elsevier Science B.V. All rights reser ved.