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 conditon, a charge accumulation of 5×10 11 cm −2 is obtained. The importance of band-gap renormalization in resonant-tunneling process is also indicated