EXTRINSIC PHOTOCONDUCTIVITY FROM EDGE DISLOCATIONS IN GERMANIUM

Extrinsic photoconductivity on plastically deformed germanium containing predominantly pure edge dislocation arrays were investigated. Conductivity and transient and steady-state photoconductivity were measured on Hall-type samples for current flow parallel and perpendicular to the dislocations. Dislocation photoresponse was observed to be strongly anisotropic with slow nonexponential decay requiring many minutes to achieve steady state at nitrogen temperature. The results are consistent with grain boundary-type potential barriers forming on active slip planes as edge dislocations accept electrons. The spectral response indicates a band of dislocation acceptor states with the majority of trapped electrons located 0.4 to 0.6 eV below the conduction band. © 1969 The American Institute of Physics.