THERMIONIC ELECTRON-EMISSION FROM NARROW BAND-GAP SEMICONDUCTORS UNDER PICOSECOND LASER EXCITATION

A model is presented to relate picosecond laser induced thermionic ele ctron emission to the carrier and phonon dynamics of semiconductors. S ilicon is chosen as a model material since its optical and thermal pro perties are well characterized. The temporal profiles of thermionic em ission current and total electron yield are obtained as a function of incident laser fluence for different surface conditions, below the sil icon surface melting threshold. Two distinct regimes have been found f or the dependence of the electron yield on the laser fluence due to th ermionic emission and this behavior is related to Auger recombination.