Growth and Characterization of Nitrogen-Doped MgSe/ZnSeTe Superlattice Quasi-Quaternary on InP Substrates and Fabrication of Light Emitting Diodes

Superlattice quasi-quaternaries (SL-QQs), consisting of MgSe/ZnSeTe short-period superlattices, were grown on InP substrates by molecular beam epitaxy with nitrogen p-doping. By changing the Mg composition (i.e., the layer thickness ratio of MgSe in the superlattice) from 0 to 0.76, the photoluminescence peak energy at 15 K increased from 2.11 to 2.68 eV. The N-doping of MgSe/ZnSeTe SL-QQs was performed by two processes, that is by the modulation-doping into ZnSeTe and by the all-doping. For the modulation-doping, a hole concentration of over 1×1018 cm-3 was obtained for Mg composition of less than 0.14, with decreased monotonically with increasing Mg composition. The hole concentration increased by changing the doping process from the modulation-doping to the all-doping. For example, the hole concentration increased from 1×1015 to 3×1017 cm-3 for Mg composition of 0.4. ZnCdSe/MgZnCdSe(Te) light emitting diodes (LEDs) were fabricated using MgSe/ZnSeTe SL-QQs as p-cladding layers having yellow emissions around 577 nm at 77 K.