Air-Stable Room-Temperature Mid-Infrared Photodetectors Based on hBN/Black Arsenic Phosphorus/hBN Heterostructures

Abstract

Layered black phosphorus (BP) has attracted wide attention for mid-infrared photonics and high-speed electronics, due to its moderate band gap and high carrier mobility. However, its intrinsic band gap of around 0.33 electronvolt limits the operational wavelength range of BP photonic devices based on direct interband transitions to around 3.7 μm. In this work, we demonstrate that black arsenic phosphorus alloy (b-As P) formed by introducing arsenic into BP can significantly extend the operational wavelength range of photonic devices. The as-fabricated b-AsP photodetector sandwiched within hexagonal boron nitride (hBN) shows peak extrinsic responsivity of 190, 16, and 1.2 mA/W at 3.4, 5.0, and 7.7 μm at room temperature, respectively. Moreover, the intrinsic photoconductive effect dominates the photocurrent generation mechanism due to the preservation of pristine properties of b-AsP by complete hBN encapsulation, and these b-AsP photodetectors exhibit negligible transport hysteresis. The broad and large photoresponsivity within mid-infrared resulting from the intrinsic photoconduction, together with the excellent long-term air stability, makes b-AsP alloy a promising alternative material for mid-infrared applications, such as free-space communication, infrared imaging, and biomedical sensing.

2D V‐V Binary Materials: Status and Challenges

“…In Figure c, the peak D * of junction at room temperature reaches to 9.2 × 10 9 Jones, which is higher than the value obtained in 3–5 µm range of incident light. Subsequently, h‐BN encapsulation was developed to protect α‐AsP against degradation and preserve its intrinsic photoconductive effect . The photodetector based on h‐BN/α‐AsP/h‐BN heterostructure and the corresponding photoresponse performance are shown in Figure d–f.…”

“…For instance, 2D As‐P binary material (black AsP monolayer) has been predicted as a promising alternative material for solar cell due to its favorable direct bandgap, exceeding 14 000 cm 2 V −1 s −1 mobility, and high power conversion efficiency (PCE) . Exhilaratingly, experimental researches have proved that 2D black AsP is also a potential candidate for application in mid‐infrared (MIR) optoelectronics . In addition, other 2D V‐V binary materials, such as SbP, SbAs, BiSb, have been predicted to possess a considerable bandgap and a high carrier mobility, which are necessary properties for next‐generation electronic devices …”

Design strategies for two‐dimensional material photodetectors to enhance device performance

“…Even, Mittendorff et al realized a graphene‐FET terahertz photodetector with a 10 THz detection region . Moreover, BP has the intermediate bandgap between graphene and MoS 2 , enabling it to achieve high performance detectors at 3 to 5 μm, especially black arsenic phosphorus (b‐As x P 1− x ) extending the detection region to 8 μm . Except many high responsivity heterojunction graphene detectors in visible NIR, high performance detectors in LIR region remains to be resolved.…”

“…144 Moreover, BP has the intermediate bandgap between graphene and MoS 2 , enabling it to achieve high performance detectors at 3 to 5 μm, 145,146 especially black arsenic phosphorus (b-As x P 1−x ) extending the detection region to 8 μm. 147,148 Except many high responsivity heterojunction graphene detectors in visible NIR, high performance detectors in LIR region remains to be resolved. As displayed in Figure 12, there is still many high performance blanks are waiting for us to fill in and each type of detector exhibits its own advantages.…”

Negative Terahertz Conductivity at Vertical Carrier Injection in a Black-Arsenic-Phosphorus–Graphene Heterostructure Integrated With a Light-Emitting Diode

“…The latter reinforces the interband population inversion in the GL and the effect of its negative dynamic conductivity. Recent advances in the b-As 1−x P x -based heterostructure fabrication (see, for example, [29][30][31][32] are in favor of the feasibility of the proposed lasers. Figure 1 shows the schematic band diagram of the device under consideration.…”