Resonant Tunneling through quantum wells up to 2.5 THz

We have observed resonant tunneling through a single quantum well of GaAs between two barriers of GaAlAs. The current singularity and negative resistance region are dramatically improved over previous results. Approximate agreement with a simple theory has been obtained. Detection and mixing experiments carried out at frequencies as high as 2.5 THz show the intrinsic response time to be less than 10
⁻¹³
sec.