H‐BN‐Encapsulated Uncooled Infrared Photodetectors Based on Tantalum Nickel Selenide

Abstract

Uncooled broadband spectrum detection, spanning from visible to mid‐wave‐infrared regions, offers immense potential for applications in environmental monitoring, optical telecommunications, and radar systems. While leveraging proven technologies, conventional mid‐wave‐infrared photodetectors are encumbered by high dark currents and the necessity for cryogenic cooling. Correspondingly, innovative low‐dimensional materials like black phosphorus manifest weak photoresponse and instability. Here, tantalum nickel selenide (Ta2NiSe5) infrared photodetectors with an operational wavelength range from 520 nm to 4.6 µm, utilizing a hexagonal boron nitride (h‐BN) encapsulation technique are introduced. The h‐BN encapsulated metal‐Ta2NiSe5‐metal photodetector demonstrates a responsivity of 0.86 A W−1, a noise equivalent power of 1.8 × 10−11 W Hz−1/2, and a peak detectivity of 8.75 × 108 cm Hz1/2 W−1 at 4.6 µm under ambient conditions. Multifaceted mechanisms of photocurrent generation in the novel device prototype subject are scrutinized to varying wavelengths of radiation, by characterizing the temporal‐, bias‐, power‐, and temperature‐dependent photoresponse. Moreover, the photopolarization dependence is delved and concealed‐target imaging is demonstrated, which exhibits polarization angle sensitivity and high‐fidelity imaging across the visible, short‐wave, and mid‐wave‐infrared bands. The observations, which reveal versatile detection modalities, propose Ta2NiSe5 as a promising low‐dimensional material for advanced applications in nano‐optoelectronic device.

Ultrasensitive Near-Infrared Polarization Photodetectors with Violet Phosphorus/InSe van der Waals Heterostructures

“…Encapsulating with a few layers of h-BN is proven to protect the device from degradation and maintain its optoelectronic properties for up to several months, as mentioned in previous research reports. 33,34 The optical image of the device and its corresponding thickness are depicted in Figure S6. For the sake of enhancing the charge carrier separation at the surface and thus enhancing the photodetection performance of the device, a few layers of graphene were inserted in between the heterostructure of Vp/ InSe to form the VP/Gr/InSe vdW heterostructure.…”

Symmetry-Reduction Enhanced Polarization-Sensitive Photoresponse Based on One-Dimensional van der Waals Materials

“…The photoresponse performance of the 1D vdW Nb 2 Pd 1– x Se 5 photodetectors is further evaluated by several vital parameters, , including responsivity ( R ), detectivity ( D *), external quantum efficiency (EQE), and rising/decay time, which have been presented in detail in Note S1 in the Supporting Information. Figure (e) presents the calculated R and D * under a 638 nm laser with different power densities at a gate voltage of 40 V. A maximum R of ∼1 A/W is achieved at a gate voltage of 40 V because the photogating-effect-dominated photocurrent generation mechanism could extend the lifetime of photoexcited carriers .…”

Bias-dependent photoresponse of Td-WTe2 grown by chemical vapor deposition

“…However, when the bias voltage varies from 1 to 2 mV, the slight increasing of τ res and τ rec is due to the enhancement in Joule heat effect and increasing of the transport time of carriers. Therefore, the photobolometric effect may be introduced to the photoresponse as the bias voltage increases from 2 to 3 mV [35][36][37]. This effect is based on the change in resistivity of the material caused by uniform heating under light exposure, which alters the magnitude of the current under external bias voltage and light exposure [38,39].…”