ROOM-TEMPERATURE OBSERVATION OF PHOTOCURRENT DEPENDENCE ON APPLIED BIAS IN SI1-XGEX SI MULTIQUANTUM WELLS/

We report the observation of the dependence of photocurrent on applied bias in Si1-xGex/Si multiquantum wells at room temperature. The photo currents were measured on reverse biased p-i-n diodes containing an in trinsic region comprised of Si1-xGex/Si multiquantum wells. These Si1- xGex/Si multiquantum wells were grown by the remote plasma enhanced ch emical vapor deposition method. Using the technique employed by Park e t al. [J. Vac. Sci. Technol. B 8, 217 (1990)] to analyze similar exper imental observations at lower temperature (77 K), we have estimated th e absorption edges from the photocurrents and showed a large transitio n energy shift under electric field. The observed shape of the absorpt ion coefficient as a function of the photon energy differs from that o bserved previously at lower temperature.