Photoluminescence characterization of MBE grown Zn1-xBexSe

We report photoluminescence (PL) studies of high-quality Zn1-xBexSe films g rown by molecular beam epitaxy (MBE) on GaAs substrates by use of a novel g rowth method of Be-Zn co-irradiation before the growth of a thin ZnSe buffe r layer. Samples show double-crystal X-ray linewidth as narrow as 23 arcsec . Low-temperature (13 K) PL of undoped samples showed free exciton emission , which defined the bandgap and showed that this system gives bandgap bowin g. In addition, there was dominant deep bound excitonic recombination. We a lso suggest that deep PL can be caused by low structural quality of films, rather than by specific impurity states. Nitrogen-doped samples (with net a cceptor concentrations up to 2 x 10(17) cm(-3)) show strong impurity relate d photoluminescence. (C) 2000 Elsevier Science B.V. All rights reserved.