Behavior of Lead Sulfide Photocells in the Ultraviolet*

Abstract

Spectral response measurements have been made on Eastman Kodak lead sulfide cells in the wavelength range 0.2–2.0 μ. The quantum sensitivity (defined as the number of electronic charges passed in the external circuit per incident photon) is roughly constant for wavelengths greater than 0.6 μ, but rises linearly with photon energy at shorter wavelengths. The increase in quantum yield is attributed to electron multiplication by secondary internal emission.