Towards broadband, low-capacitance, far-infrared photoelectric tunable-step detectors

A new quantum phenomenon, the in-plane photoelectric effect, has recently been discovered as a mechanism of far-infrared (FIR) photoresponse generation in a two-dimensional electron gas (2DEG). This effect has shown promise for terahertz (THz) detection due to its high photoconversion efficiency and a lack of an intrinsic response time limit. Initial detectors utilizing the in-plane photoelectric effect, known as Photoelectric Tunable-Step (PETS) detectors, have been developed and demonstrated to work as high-sensitivity FIR detectors. Here, we propose a PETS detector utilising a novel, broadband antenna adopted from a wide bow-tie geometry that minimizes the area of 2DEG covered by the antenna. We demonstrate experimentally a large photoresponse to 2.0 THz radiation of an AlGaAs/GaAs heterojunction-based PETS detector with our novel antenna design. Under the same operating conditions, this detector shows much larger photocurrent and two-times improvement in rise time compared to an identical PETS detector fabricated simultaneously on the same chip but instead incorporating a bow-tie antenna. Our findings help facilitate the development of future high-speed, low-noise, ultra-sensitive FIR detector arrays.