Modulated Photoconductivity Studies of a-As_2Se_3 Thin Films


Abstract: Modulated photocurrent measurements in amorphous arsenic triselenide (a-As_2Se_3) is reported. Particular focus is paid towards photocarrier lifetimes as a function of temperature, and applied electric field (i.e. dc) were determined by using the quadrature frequency-resolved spectroscopy method. The activation energy from the photocurrent as a function of temperature was determined to be about 125 meV for a constant illumination intensity of 2.3 mW. Its value was found to be almost independent of the applied electric field. The exponent \nu in the power law relationship (I_{ph} \propto G^v) between generating flux and photocurrent was obtained under different electric fields. The electric field dependence of photocurrent at various temperatures was also measured. A very little non-ohmic contact behavior was observed at low fields and at high temperatures.

Keywords: Amorphous As_2Se_3, Photoconduction, recombination, lifetime, trapping.

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