Ambient temperature long‐wavelength infrared (LWIR) photodetection has many critical applications ranging from thermal imaging and optical communications to night vision cameras. Currently, high performance, low cost, air stability, and ultra‐broadband response still constitute challenges. Here, the study demonstrates a high‐performance uncooled LWIR photodetector using 2D hexagonal α‐Fe2O3 single crystal nanoflakes, which are synthesized via chemical vapor deposition. The 2D α‐Fe2O3 photodetector realizes high specific detectivity (D*) of 3.28×109 cmHz1/2 W−1 and very low noise equivalent power of 8.94×10−14 W Hz−1/2 with 10.6 µm laser. The photo bolometer effect is responsible for the photoresponse in the infrared range with a large temperature coefficient resistance of −241.2% K−1. This study shows a new type of potential broadband response material and provides a promising LWIR optoelectrical device with good air stability.

The type‐II band‐aligned van der Waals (vdW) heterostructures are favorable for photocarrier separation and are often used for designing high‐performance photodetectors. Inspired by this, a metal‐mirror electrode enhanced HfSe2‐InSe vdW heterostructure photodetector is designed and demonstrated excitement performance in UV light detection. It is demonstrated the moderate bandgap heterostructure can be configured as a high‐performance UV photodetector with excellent light on/off ratio of 106, high photoresponsivity of 47.3 AW−1, competitive high specific detectivity of 3.2 × 1012 cmHz1/2W−1 and very low noise equivalent power of 2.8 × 10−16 WHz−1/2. Notably, the photoresponse speed of the device is very fast, with a rise time of 4.1 µs and a decay time of 5.4 µs. The results indicate that 2D HfSe2‐InSe vdW heterostructure possesses great potential applications in UV photodetection.

Highly sensitive uncooled mid-wave infrared (MWIR) photodetectors have a very wide range of applications ranging from the sensor and image to communications. Traditional MWIR detection semiconductors require liquid nitrogen cooling to depress dark current, which impeded the wide applications of devices. Here, we report a metal electrode-enhanced double parallel BP/InSe/BP van der Waals heterostructure uncooled MWIR photodetector. The device exhibits ultrahigh light on/off ratio of 108 and a very low dark current of 0.16 pA. The competitive performance includes high photoresponsivity ( R) of 27.8 A W−1, excellent specific detectivity ( D*) of 3.8 × 1012 cm Hz1/2 W−1, very low noise equivalent power (NEP) of 3.7 × 10−16 W Hz−1/2, and fast response speed of τr = 3.5  μs and τd = 2.4  μs in the visible range. Notably, in the MWIR range, the light on/off ratio of ∼104, NEP of 3.0 × 10−13 W Hz−1/2, and D* of 4.8 × 109 cm Hz1/2 W−1 was realized. The work sheds light on developing a high-performance uncooled MWIR photodetector by designed band alignment.