Bi2Se3/PtSe2 heterostructure ultra-broadband UV-to-THz negative photoconductive photodetectors with wide-temperature-range operation

Abstract

Ultra-broadband photodetectors have important applications in biomedical imaging, environmental monitoring, optical communication, and space exploration, etc. The need for wide temperature range adaptation in extreme environments (e.g., infrared guidance, space exploration) is particularly urgent. However, existing technologies face the following bottlenecks: first, traditional semiconductor detectors are limited to a single spectral response, ultra-wideband detection requires multi-device integration, and in the terahertz band there is a physical limitation of the mismatch between the photon energy and the material bandgap. Second, carrier scattering at high temperatures leads to a sudden drop in mobility and degradation of the optical response. Finally, the development of devices based on the negative photoconductivity effect is still in the exploratory stage, which limits the engineering applications. In this study, we have innovatively integrated photothermoelectric effect (PTE), joule thermal effect (JHE) and photoinduced bolometric effect (PBE) multi-physics mechanisms by constructing Bi2Se3-PtSe2 heterojunction, which realizes broad-spectrum UV-Terahertz (405 nm-0.1 THz) detection and stable operation in a wide temperature region of 183-501 K. Under zero bias, the device exhibits a self-powered positive optical response in the 405-1550 nm band based on the photothermoelectric effect. When bias voltage is applied, the negative photoconductive response is triggered by the synergistic Joule heating and optical radiothermal effect, with peak responsivity (R) of 44.45-83.6 A/W, specific detection rate (D*) of up to 4.63×107 Jones, and noise equivalent power (NEP) as low as 1.37×10-13 W/Hz1/2. Temperature characterization tests show that R/D*/NEP is optimized to 78.19 A/W/5.75×107 Jones/1.09×10-13 W/Hz1/2 under 1550nm illumination and 183K. Even at 501K, the device maintains 11.24 A/W responsivity and 7.9×106 Jones detection sensitivity. The present work breaks through the limitations of the traditional negative photoconductivity effect in terms of detection bandwidth and temperature stability through a multi-mechanism synergistic strategy, providing a theoretical basis and technical path for the design of a new generation of broad-spectrum photodetectors.