CAPACITANCE ANOMALY IN THE NEGATIVE DIFFERENTIAL RESISTANCE REGION OFRESONANT-TUNNELING DIODES

For In0.53Ga0.47As/AlAs resonant tunneling diodes, the peak structure in the capacitance-voltage (C-V) characteristics in the negative diffe rential resistance.(NDR) region was investigated. We experimentally re veal that the electron sheet density that is responsible for the capac itance peak is equal to half of that in the quantum well at the peak v oltage. The derived electron sheet density in the quantum well at the peak current is 3.2 x 10(11) cm(-2) and the resulting electron lifetim es in the quantum well are 320 and 580 fs for 2.0- and 2.3-nm AlAs bar riers.