Realization of Terahertz Self-Mixing Detectors Based on AlGaN/GaN HEMT

Abstract

In this chapter, the fabrication, characterization, and optimization of self-mixing terahertz field-effect detectors based on AlGaN/GaN 2DEG are introduced in details. By fabrication, five different detectors are made to uncover the self-mixing mechanism and search for an optimized detector design. By characterization, we not only obtain the I - V characteristics, the responsivity, the noise-equivalent power, the response spectrum, the response speed, the polarization effect, etc, but also we probe the localized self-mixing photocurrent based on which the quasi-static detector model and the design of asymmetric antenna are verified. Under the guidance of the detector model, we focus on the design of terahertz antennas and field-effect gate to improve the detector responsivity and sensitivity. An asymmetric antenna with three dipole blocks is found to be the most effective antenna among the five different designs. A design rule for high-sensitivity terahertz detectors is given.