Photoassisted metalorganic vapor-phase epitaxy of ZnSe on GaAs

Photoassisted growth of ZnSe on (100) GaAs substrates by a metalorganic vapor-phase epitaxy process was carried out using dimethylzinc and ditertiarybutylselenide as precursors. Illuminating the surface of the layer during the growth with a high intensity xenon arc lamp, the growth rate was strongly enhanced, only when the photon energy selected by the narrowband interference filters (10 nm bandwidth) was higher than the ZnSe bandgap energy. X-ray diffraction patterns as well as energy-dispersive X-ray spectra were used to determine the crystalline quality and the chemical composition of the ZnSe layers grown under different conditions. The photo-induced charge transfer (photocatalysis) and the supersaturated Se film mechanism are discussed to explain the large enhancement of the growth rate (factor ∼ 3) observed under irradiation.