Abstract

Resonant tunneling devices have recently been used as detectors and mixers to demonstrate that the nonlinearities and negative resistance persist even up to 2.5 THz(1), and that oscillations at microwave frequencies are possible using the negative resistance(2). This presents a unique opportunity to explore the physics and device possibilities in semiconductors on time scales of 100 fs. During our investigations of fast processes, additional phenomena with other time constants were observed. One effect which has been studied in detail is attributed to persistent photoconductivity which involves ionization of DX centers(3) in the AlGaAs barriers. Another effect is observed by mixing two optical beams of above-band-gap radiation with a high difference frequency.

© 1985 Optical Society of America