Blackbody-sensitive room-temperature infrared detection is a notable development direction for future low-dimensional infrared photodetectors. However, because of the limitations of responsivity and spectral response range for low-dimensional narrow bandgap semiconductors, few low-dimensional infrared photodetectors exhibit blackbody sensitivity. Here, highly crystalline tellurium (Te) nanowires and two-dimensional nanosheets were synthesized by using chemical vapor deposition. The low-dimensional Te shows high hole mobility and broadband detection. The blackbody-sensitive infrared detection of Te devices was demonstrated. A high responsivity of 6650 A W⁻¹ (at 1550-nm laser) and the blackbody responsivity of 5.19 A W⁻¹ were achieved. High-resolution imaging based on Te photodetectors was successfully obtained. All the results suggest that the chemical vapor deposition–grown low-dimensional Te is one of the competitive candidates for sensitive focal-plane-array infrared photodetectors at room temperature.

An infrared photodetector is a critical component that detects, identifies, and tracks complex targets in a detection system. Infrared photodetectors based on 3D bulk materials are widely applied in national defense, military, communications, and astronomy fields. The complex application environment requires higher performance and multi-dimensional capability. The emergence of 2D materials has brought new possibilities to develop next-generation infrared detectors. However, the inherent thickness limitations and the immature preparation of 2D materials still lead to low quantum efficiency and slow response speeds. This review summarizes 2D/3D hybrid van der Waals heterojunctions for infrared photodetection. First, the physical properties of 2D and 3D materials related to detection capability, including thickness, band gap, absorption band, quantum efficiency, and carrier mobility, are summarized. Then, the primary research progress of 2D/3D infrared detectors is reviewed from performance improvement (broadband, high-responsivity, fast response) and new functional devices (two-color detectors, polarization detectors). Importantly, combining low-doped 3D and flexible 2D materials can effectively improve the responsivity and detection speed due to a significant depletion region width. Furthermore, combining the anisotropic 2D lattice structure and high absorbance of 3D materials provides a new strategy in high-performance polarization detectors. This paper offers prospects for developing 2D/3D high-performance infrared detection technology.

The performance of the long-wavelength infrared (LWIR) HgCdTe photodetectors with nBn structure is susceptible to the thickness of barrier layer and the huge mismatch of the energy band between the barrier layer and the absorption layer. Herein, a numerical simulation analysis for LWIR HgCdTe nBn device is carried out to present an enhanced performance with optimized structural and physical parameters (including thickness, doping concentration, and composition). The results provide that the valence band-offset (VBO) could be reduced by structure optimization, and could greatly improve the transport properties of photogenerated carriers. In addition, the effect of composition diffusion caused by the annealing process has also been studied to demonstrate that larger composition diffusion leads to a much higher dark current. The model and calculation results established in this article can provide important theoretical support and guidance for further researches of LWIR HgCdTe nBn devices.

In this article, the performance of midwavelength infrared (MWIR) HgCdTe electron avalanche photodiodes (e-APDs) with variable annealing processes and guard ring design is investigated. Carrier distribution in the device is performed by simulation methods to better understand the mercury interstitial dynamic transport mechanism. It is found that the device with suitable annealing time can effectively reduce the dark current while maintaining the bandwidth at a high level. Surface leakage current and the effect of guard ring design in ion implanted-type HgCdTe e-APDs are clarified by the electric-field distribution. The simulated results show that the dark current, excess noise factor, and mean square noise can be decreased with a guard ring design. In addition, the temperature-dependent performance of HgCdTe e-APD with guard ring is simulated, indicating optimization operating window. This article demonstrates the significance of guard ring designs for HgCdTe APDs, and the simulation method will provide an effective way to determine the source of the current generation mechanism.