Temperature dependence of the relaxation time of photoconductivity and non-steady-state photocurrents in photorefractive Bi12SiO20 grown in an oxygen-free atmosphere

We present temperature measurements of the non-steady-state photocurrent an d photoconductivity relaxation time in photorefractive sillenite crystal Bi 12SiO20 grown in an oxygen-free atmosphere. The obtained dependencies are e xplained using a conventional model of semiconductor crystal with shallow e nergy level. The activation energy of shallow level obtained from photocurr ent measurements was found to be E-T=(0.45 +/- 0.11) eV. Independent measur ements of the temperature dependence of the relaxation time of photoconduct ivity are in reasonable agreement with this estimation and give the value f or E-T equal to (0.56 +/- 0.01) eV. (C) 1999 American Institute of Physics. [S0003-6951(99)02230-5].