Photoconductivity of KBr ContainingFCenters

The quantum efficiency or number of conduction-band electrons produced per absorbed photon in the region of the $L$ bands at 21°K in KBr was found to be nearly unity. Photoconductivity measurements indicated that the $L$ bands are due to electronic transitions to energy levels which are in the conduction band and that the $K$ band is composed of two or more overlapping optical-absorption bands, of which the higher energy ones are due to electronic transitions to the conduction band. The temperature dependence of the $L$-band photoconductivity below 45°K can be explained by the temperature dependence of the mobility.