Transient Photoconductivity and Deep Trapping Processes in Amorphous Hydrogenated Silicon

Procedures for obtaining electronic density-of -states (g(E)) estimates from transient photoconductivity measurements in strongly disordered semiconductors are presented using a multiple-trapping description of transport. Both the transient drift mobility and the total trap density must be determined to obtain an estimate. Using large laser intensity saturation effects we estimate g(E) in undoped amorphous, hydrogenated silicon (a-Si:H) specimens. In addition, the trap attempt-to-escape frequency, v , is also estimated and the validity of the multiple -trapping model to this material is evaluated. The results suggest a wider application for transient photocurrent measurements in the characterization of disordered semiconductors.