Photoluminescence dynamics of the layered GaSe semiconductor under Intense picosecond laser-induced shock waves

Abstract

The generation of intense picosecond laser- driven shock waves in the layered GaSe semiconductor and simultaneous probing of the sample using another picosecond laser to study the shock- induced phenomena are discussed. In unshock condition, at low probe intensity, spontaneous emission is observed while at high probe intensity stimulated emission is observed. Under laser- induced shock pressure, 20-nm spectral shift of spontaneous emission and sixfold decrease in the intensity of stimulated emission have been detected. By careful band-shape analysis, both spontaneous and stimulated emission is attributed to the exciton-exciton scattering process. The red shift of the spontaneous emission is caused by the shrinkage of GaSe band gap under shock pressure. The quenching of the stimulated emission is explained on the basis of stimulated absorption by the electron-hole recombination process.