Abstract
A molecular beam epitaxial grown GaAs three-terminal device with a delta-doped barrier and GaInAs quantum well exhibiting controllable S-shaped negative differential resistance and switching voltages has been fabricated and tested. The device has a large potential barrier between the anode and cathode regions which can be modulated via a third terminal. The modulation of the potential barrier has a substantial effect on the switching behavior of the device. For the devices having a cathode contact area of 50 μm 2 , a spectrum analyzer reveals unstable oscillation up to the system measurement limit of 21 GHz. The output power signal for the best device is greater than -10 dBm which is 20 dB above the noise floor at 20.8 GHz. The results show this device to be a potentially useful and promising high-frequency oscillator.