High sensitivity HgTe room temperature terahertz photodetector

Abstract

The advent of topological semi-metals with peculiar band structure and exotic quantum-transport provides novel pathways for upgrading the performance of terahertz (THz) detection. HgTe is among such a candidate with the unique advantages of a negative bandgap, ultra-high mobility, and thermoelectricity, which ignites the possibility of addressing the technical bottlenecks of traditional routes for THz detection. Herein, for the first time, we report large-area (3 in.) growth of high-mobility HgTe thin-film via molecular-beam epitaxial and the implementation of bow-tie antennas based HgTe THz-detector with the abilities of ultrafast response, low noise, and high ambient-stability at room temperature. By exploration of strong light-coupling and superior hot-carrier transport, the bow-tie antenna-based HgTe photodetector can achieve a responsivity of 0.04 A/W and a noise equivalent power of less than 0.6 nW/Hz1/2 at 0.3 THz. Furthermore, the sensitivity can be further improved by nearly an order of magnitude up to 0.36 A/W at 0.3 THz by incorporating a short channel asymmetric cubic resonator. The reported performances allow a realistic exploration of high-mobility bulk states in topological semimetals for large area, fast-imaging applications in the THz band.