A kinetic model for photo-assisted growth, based upon the formation of H radicals by reaction with H carrier gas, appeared to reveal a fundamental obstacle to active N doping. Attempts at growth using He carrier gas resulted in a lack of growth under a range of conditions. An alternative approach to activation of the dopant was post-growth annealing. Experiments on a combination of cooling under N, and annealing at higher temperatures, showed that high-temperature annealing was the critical step in reducing H carrier gas. However, this annealing increased the concentration of deep levels; perhaps due to the formation of Zn vacancies.

In situ Post-Annealing Treatment of Nitrogen-Doped ZnSe Grown using Photo-Assisted MOVPE M.U.Ahmed, S.J.C.Irvine: Journal of Electronic Materials, 2000, 29[1], 169-72