Electronic Excitations in Response to Gas-Surface Interactions

We have optically excited carriers and followed their recombination kinetics in order to determine the effects of the physical and chemical states of the semiconductor surfaces on their electronic properties. Carrier recombination is measured as a function of excess carrier density as determined by the change in conductivity of a crystal illuminated for a few msec by HeNe or HeCd lasers at incident powers over the range 1 nW to 10 mW.