Electric-field effects on confined hydrogenic impurities in semiconductors

We report the observation of electric-field effects on the electronic states of shallow impurities confined in semiconductor quantum wells. As p-i-n diode structure was used to produce the controllable electric field, and the states of donors doped in the well center were monitored by far-infrared magnetospectroscopy. A broadened, impurity-related peak is observed, which changes signficantly both in shape and in position with electric field. Observed shifts and changes in the line profile are in good agreement with a variational calculation that incorporates the impurity distribution within the well.