High-frequency amplification and generation in charge injection devices

Abstract

Room-temperature high-frequency measurements on a three-terminal amplifying device based on real-space hot-electron transfer between two conducting layers separated by a potential barrier have been performed. The devices grown by organometallic chemical vapor deposition utilize a novel undoped GaAs/AlGaAs heterostructure which, through its dramatically reduced parasitic leakage compared to previous structures, permits, for the first time, operation as a charge injection transistor. The charge injection transistor exhibits true three-terminal amplification due to real-space hot-electron transfer controlled by electron temperature in a high mobility channel. The device demonstrates power and current gains with cut-off frequencies of 9.8 and 29 GHz, respectively, with maximum current gain of 39 dB. In the negative resistance transistor mode, the same device was found capable of microwave generation up to 7.7 GHz. The frequency response of our device is shown to be limited by RC in the output circuit and methods for improvement of the cut-off frequency are discussed.