Charge accumulation in a double-barrier resonant-tunneling structure studied by photoluminescence and photoluminescence-excitation spectroscopy

Charge accumulation in the quantum-well region of a double-barrier AlGaAs/GaAs resonant-tunneling-diode structure is studied by using photoluminescence and photoluminescence-excitation spectroscopy. The observed optical spectra are found to change systematically with an applied bias and make it possible to directly determine the charge accumulation under various biasing conditions. At the resonant condition, a charge accumulation of 5×${10}^{11}$ ${\mathrm{cm}}^{\mathrm{-}2}$ is obtained. The importance of band-gap normalization in resonant-tunneling process is also indicated.