Refractive Index Measurements of BeZnTe and Related Superlattices on InP and Application for Waveguide Analysis of MgZnCdSe/BeZnTe Visible Lasers
Abstract
Refractive indices of BeZnTe, ZnCdSe/BeZnTe superlattices (SLs) and MgSe/BeZnTe SLs grown on InP substrates were measured for the first time. The refractive index of BeZnTe with a wide bandgap (Eg) of 3.12 eV was higher than that of ZnCdSe with a narrower Eg of 2.1 eV. This tendency in BeZnTe is unexpected, because for other materials, wider bandgaps may generally give lower indices. The refractive indices of the ZnCdSe/BeZnTe and MgSe/BeZnTe SLs were controlled in the wide range by changing the layer thickness combination. Waveguide analysis is performed for laser structures consisting of ZnCdSe/BeZnTe SL active layer and MgSe/BeZnTe SL p-cladding layer. As a result, optical confinement factors around 5.9% are estimated at a wavelength of 564 nm.
