Novel solid state terahertz detectors and emitters.

摘要

This thesis demonstrates prototypes of novel solid-state sub-terahertz and terahertz detectors and emitters. These types of detectors and emitters can be used in a wide range of potential applications, including wireless communication for above 60 GHz at data rates up to 155 Mb/s, high-performance miniaturized military radars and sensors, far-infrared spectrum analysis, poisonous chemical-compound and biological-agent identification, medical imaging, weather forecasting, plasma diagnostics, and wireless interconnects on future chips. In principle, the sensitivity of the resonant THz FET detector investigated in this thesis could exceed that of present-day Schottky barrier detectors by many orders of magnitude, depending on the plasma frequency and the electron scattering time.; Our detector and emitter prototypes are based on deep-submicron and micron field-effect transistors operating in a new regime: one exhibiting excitation of plasma-wave oscillations within the 2D FET inversion-channel. In this newly discovered regime, deep-submicron FETs can operate as emitters and detectors of terahertz radiation corresponding to the oscillation frequency of plasma waves, which is much higher than the conventional FET electrical cutoff frequency.; We present the results of a theoretical analysis for plasma-wave terahertz detection and emission in Si, GaAs, and GaN FETs. We also present results of experimental studies involving sub-terahertz and terahertz detection of GaAs and GaN FETs, and involving sub-terahertz emission of GaN FETs. To perform our experiments, we designed and implemented sub-terahertz detection, emission, and mixing systems; and developed the mathematical techniques that allowed us to extract the emission spectrum from the Fabry-Perot interferometer response. Experimental results for the resonant and non-resonant detection are all in good agreement with our theory. The emission spectrum has a frequency peak higher than the device cut-off frequency but lower than the radiation frequency predicted by our theory because of what we believe is a possible effect of ungated channel regions within the device.