DOUBLE PEAK SPECTRA IN SPONTANEOUS EDGE ELECTROLUMINESCENCE

An experimental and theoretical study of the shape of spontaneous elec troluminescent spectra, emitted from the edge of GaxIn1-xAsyP1-y/InP h eterostructure diodes, is reported. The occurrence of double peak spec tra in some samples is explained in terms of selective internal absorp tion along the way to the edge. Numerical evaluation of spontaneous lu minescence and corresponding gain or absorption coefficient is present ed within the framework of usual band structure approximations. Propag ation towards the diode edge is treated using a transverse mode guidin g approach. Hence we go beyond the geometrical optics and show that th e spectral shape can be interpreted as a manifestation of the fundamen tal and/or first-order mode during propagation towards the edge.