ANALYSIS AND SIMULATION OF THE QUANTUM WELL INJECTION TRANSIT-TIME DIODE

The quantum-well injection transit time (QWITT) diode is simulated for two different injection phase angles (90° and 270°) at 60, 90, 200, and 300 GHz. Quantitative analysis of the output power and efficiency is carried out by including the velocity transient effect, the diffusion effect, and the carrier space-charge effect. The diffusion effect and the carrier space-charge effect degrade the output power and efficiency of the device. The velocity transient effect enhances the device performance for a 270° injection phase mode, but it renders the device useless for a 90° injection phase mode. In comparison with other microwave devices, a simple QWITT diode is a very promising device for millimeter-wave frequency application when it is used with a 270° injection phase angle. This is due to fast intrinsic frequency response time and extremely localized carrier injection mechanism as well as high transient velocity at a small distance. Because of the good efficiency of the QWITT diode, it is feasible to increase output power by integration of many QWITT diodes.