REFRACTIVE-INDEX MEASUREMENTS OF MGZNCDSE II-VI COMPOUND SEMICONDUCTORS GROWN ON INP SUBSTRATES AND FABRICATIONS OF 500-600 NM RANGE MGZNCDSE DISTRIBUTED BRAGG REFLECTORS

Refractive indices of Mg-x(Zn0.48Cd0.52)(1-x)Se compounds grown on InP substrates were systematically investigated as a function of Mg compo sition (x). The refractive indices with various Mg compositions were e stimated from the reflectance measurements. By approximating the refra ctive indices by the modified single effective oscillator method, the direct band gap energy E-Gamma = 2.03 + 1.45x, the dispersion energy E -d = 24.5 - 15.2x, and the oscillator energy E-0 = 5.13 - 1.03x were o btained. MgZnCdSe multilayer distributed Bragg reflectors (DBRs) desig ned by using the refractive indices obtained in this study were fabric ated by a molecular beam epitaxy. As a result, high reflectance values over 98% at 595 nm were experimentally obtained for the 30 pairs 1(Zn 0.48Cd0.52)(0.9)Se/Mg-0.6(Zn0.48Cd0.52)(0.4)Se DBR, and the reflectanc e spectrum agreed with the theoretical values. Furthermore, good agree ments of the experimental and the theoretical maximum reflectance of t he DBRs as a function of the layer pair number are obtained. From theo retical investigations of 500-600 nm wavelength range DBRs, reflectanc e values of 99.9% are calculated for the layer pair numbers from 30 to 40. (C) 1997 American Institute of Physics.