Vertical tunneling photoconductivity and field domain formation in thick-barrier GaAs/AlAs superlattice diodes

Abstract

Vertical tunneling photoconductivity in thick barrier GaAs/AlAs superlattice diodes has been experimentally investigated at 18 K as a function of electric field at high and low illumination powers by photocurrent (PC) response and photoluminescence (PL) measurements. For the thick barrier SL diode, PC spectra show unusual behaviors such as negative PC peaks at the maximum positions of absorption under low field conditions. Both of the PC and PL intensities, furthermore, are enhanced under the low electric field when the excitation power is low. These PC and PL results suggest that the domain formation may occur under low excitation conditions in the thick barrier superlattice.