APPEARANCE OF A BAND OF DELOCALIZED D- STATES IN UNCOMPENSATED SILICON IN AN ELECTRIC-FIELD

The impurity photoconductivity spectra of uncompensated silicon at liq uid-helium temperatures under conditions of strongly suppressed backgr ound radiation established that the delocalization arising in the D- b and as E increases is not associated with any changes of the fluctuati on potential and is due to the direct action of the held E. A delocali zation band of finite width appears abruptly at a critical value E(c) (similar to 100 V/cm) of E. The critical field E(c) increases with the density of charged centers in the sample. (C) 1997 American Institute of Physics.