Far infrared photoconductivity studies in silicon blocked impurity band structures

We report two novel features in the photoconductive response of a boron dop ed Blocked Impurity Band (BIB) structure. In this structure which comprises a pure and a very doped photoconductive layer between ohmic contacts, spec tra of impurities at an interface with the pure layer were evidenced in a p rocess involving field assisted hopping among excited states. In addition, a peculiar photovoltaic response, with open circuit photovoltage surprising ly independent of the incident photon flux was measured and analysed. (C) 1 999 Elsevier Science B.V. All rights reserved.