Time-Resolved Optical Absorption and Mobility of Localized Charge Carriers in a-As2Se3

Abstract

The first measurements are reported of simultaneous, transient, photoinduced optical absorption (PA) and photoconductivity (PC) in an amorphous semiconductor ($a$-${\mathrm{As}}_2$ ${\mathrm{Se}}_3$). Measurements in the time range 100 ns to 1 ms show that the same density of excited carriers gives rise to both effects. PA is observed only when carriers are in localized states, whereas PC is observed for both hot carriers ($\mu \tau \simeq 7\times {10}^{-12\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{V}}^{-1\mathrm{}}$) and localized carriers.