Features of zinc sulfide film photoconductivity with conductivity ``memory''
Abstract
The contribution is determined to the magnitude of the photoresponse induced by changes in the concentration and effective mobility of free charge carriers in polycrystalline zinc sulfide films as a function of excitation conditions and the conductivity “memory” level. It is established by the method of parallel measurement of the photoconductivity (PC) at direct and microwave frequency (1010 Hz) currents that under conditions of stationary exposure at 300 K and in a high conductivity state (77 K) the film PC changes mainly because of changes in the free charge carrier concentration. Under impulsive exposure conditions (300 K) the PC is governed principally by the change in the effective free charge carrier mobility. An increase in the PC with the growth of the conductivity “memory” level is also associated with the change in effective mobility. The practical significance of the results obtained is an increase in the photoresponsiveness of the films because of application of impulsive exposure and its control by changing the conductivity “memory” level.
- Publication:
-
Soviet Physics Journal
- Pub Date:
- September 1988
- DOI:
- 10.1007/BF00895987
- Bibcode:
- 1988SvPhJ..31..752B