ULTRAVIOLET SEMICONDUCTOR-LASER STRUCTURES WITH PSEUDOMORPHIC ZNCDSSE QUATERNARY ALLOYS ON GAP SUBSTRATES

For short-wavelength laser diodes operating in the ultraviolet region, a ZnCdSSe/ZnSSe or ZnCdSSe/ZnCdS quantum well (QW) structure on a GaP substrate is proposed. The physical parameters of Zn1-xCdxSySe1-y alloys in the range of 0 less-than-or-equal-to x less-than-or-equal-to 0.3 and 0.7 less-than-or-equal-to y less-than-or-equal-to 1 are estimated to design the device structure. It is shown that this system can be grown coherently on GaP substrates and is expected to possess the so-called type I QW structures that allow the effective confinement of both electrons and holes. ZnCdSSe/ZnSSe double heterostructures grown by gas-source molecular beam epitaxy exhibited relatively strong photoluminescence from the quaternary active layer at 4.2K, which suggested carrier confinement in the active layer.