No abstract

Picosecond-laser-excited photoluminescence spectra in GaSe at room temperature have been measured and analyzed.Both spontaneous and stimulated emissions were attributed to the excitonexciton scattering process in GaSe through a careful band-shape analysis. The exciton-photon coupling coefficient~a/@=3. 3)&10 ' was obtained from the spontaneous emission spectra fit. The stimulated emission is well explained by the optical gain mechanism arising from the reverse absorption process of the exciton-exciton scattering.