Electron-Hole Pair Creation in Gallium Phosphide by α Particles

Abstract

The energy required to form one hole‐electron pair in gallium phosphide has been measured to be 7.8±0.8 eV/pair. The experimental method consisted of determining the charge produced and collected when α particles of known energy bombarded a surface barrier which had been formed by evaporating a thin layer of gold onto an etched surface of the gallium phosphide. When high‐resistivity gallium phosphide (produced by copper diffusion) was used, the α‐particle detection efficiency dropped very sharply but could be restored to almost unity efficiency by illumination. This effect is attributed to the action of traps on the charge collection process.