Capacitance of resonant tunneling diodes with spacer layers

Abstract

Self-consistent calculations have been performed on a double barrier resonant tunneling diode (RTD) with asymmetric spacer layers under various biases. The quasi-static state charge distribution in the GaAsAl 0.3Ga 0.7As RTD was studied and the capacitance derived. The theoretical capacitance-voltage ( C- V) characteristic agrees qualitatively with experimental results. In contrast to the general belief that charge accumulation in the quantum well results in the observed peak in capacitance meaurements, our results reveal that the peak is induced by the quantum well discharging process. Comparison between the theoretical and experimental results also supports the suggestion that scattering and localization effects are important in the device. Conditions for optimizing the C- V characteristic for high frequency operations are discussed.