Interaction of excitons in indirect solid solutions of In1?xGaxP at high levels of excitation

Abstract

The cathode luminescence spectra of GaP and solid solutions of In1−xGaxP (with an indirect energy band structure) obtained by liquid-phase epitaxy are investigated at T=77 and 9°K. It is established that the recombination of excitons on neutral donors and the pure exciton recombination with the participation of TA (ħω=13±1 meV), LA (ħω=31±1 meV), and TO (ħω=43±2 meV) phonons. dominate in the low-temperature luminescence spectra of GaP and In1−xGaxP with a small concentration of photon impurities. The complex luminescence band that arises for sufficiently high levels of excitation and at T = 9°K is attributed to the luminescence of an electron-hole drop (EHD). The transformation of spectral form of the EHD band with the transition from GaP to In1−xGaxP is attributed to a simultaneous reduction in the contribution of the TA and TO replicas and to the appearance of a phononless component in the luminescence of the EHD.