E-shaped patch antenna for GaAs-based broadband THz detectors

Abstract

High-performance broadband terahertz (THz) photodetectors are of great interest driven by lots of applications. To improve the performance of the THz photodetector in a wide spectral coverage, the E-shaped patch antenna with three slots is proposed and studied in theory. GaAs-based homojunction interfacial work function internal photoemission (HIWIP) broadband THz detector is used as an example to demonstrate the effect in broadband detection. Due to the combined effect of the antenna and the microcavity, E-shaped patch antenna microcavity HIWIP increase the optical coupling efficiency in a broadband range from 2.1–20 THz by an average of four times. Considering the requirement to reduce the dark current, the etched E-shaped patch antenna microcavity HIWIP only retaining the active region beneath the antenna is further investigated. In contrast to the reference HIWIP, the coupling efficiency is improved by an average of 15 times in 2.3–20 THz. The high coupling efficiency of both structures leads to the significant improvement of the responsivity, noise equivalent power, and detectivity in a wide spectral coverage theoretically, which makes it possible to realize higher operating temperatures. Such a design scheme of E-shaped patch antenna structure provides a guideline for broadband THz detectors and can be used for other THz detectors.