BREAKDOWN OF EQUILIBRIUM APPROXIMATION FOR NANOSECOND LASER-INDUCED ELECTRON-EMISSION FROM SILICON

We demonstrate that nonequilibrium carrier dynamics play a significant role in nanosecond laser-induced electron emission from semiconductor surfaces. Surface emission current and electron yields due to thermio nic and photoelectric effects are calculated for a 2 ns laser pulse ir radiation, with fluences below the threshold for melting. The photoele ctric effect is found to dominate electron emission only at low fluenc es, whereas thermionic emission from interband absorption is responsib le for electron emission at high incident fluences. The results presen t a satisfactory interpretation of experimental observations for nanos econd laser-induced electron emission from silicon. (C) 1998 American Institute of Physics. [S0003-6951(98)03036-8].