Growth of ZnSe-(Zn,Mg)(S,Se) superlattices by molecular beam epitaxy

Abstract ZnSe-(Zn,Mg)(S,Se) and MgSe-Zn(S,Se) superlattices are presented here. The first one, ZnSe-(Zn,Mg)(S,Se) is a type I structure, while the second one, MgSe-Zn(S,Se) is of type II. Both kinds of superlattices can be grown with excellent optical and structural quality which is confirmed by high resolution X-ray diffraction (HRXRD) and photoluminescence (PL). HRXRD measurements fit very well to the simulations and confirm that the mosaicity of the samples is very low. In PL an FWHM of 1.1 meV for the type I sample and 3.0 meV for the type II sample is observed. The application of the type I system is discussed in more detail: I – V measurements confirm that p-carrier transport in the vertical direction is even better than in (Zn,Mg)(S,Se) mixed crystals, making ZnSe-(Zn,Mg)(S,Se)-superlattices ideal for use in device structures such as lasers and photodiodes.