Formation of Electron-Hole Pairs in a Semiconductor by Vibrationally-Excited Molecules.

Both one-dimensional and three-dimensional models are presented for the collision of a vibrationally-excited molecule with a semiconductor surface, where the transfer of vibrational energy leads to the formation of electron-hole pairs. The transition probability P is calculated as a function of the molecule-surface distance for real two systems, HC1 InSb and HC1 PbSe, as well as for some model systems with different values of parameters. While P generally increases as the distance decreases, there are some minima at intermediate distances. The overall probability is obtained as an approximate integral of P over the distance, and for thermal collisions values of a few percent are obtained. Such values are high enough for an experimental observation of electrical conductivity due to electron-hole pair formation. Author