Highly Polarized and Fast Photoresponse of Black Phosphorus‐InSe Vertical p–n Heterojunctions

Abstract

The van der Waals heterojunctions of 2D materials offer tremendous opportunities in designing and investigating multifunctional and high-performance electronic and optoelectronic devices. In this study, a vertical p-n diode is constructed by vertically stacking p-type few-layer black phosphorus (BP) on n-type few-layer indium selenide (InSe). The photodetector based on the heterojunction displays a broadband and gate-modulated photoresponse under illumination. More importantly, by taking advantage of the strong linear dichroism of BP, the device demonstrates a highly polarization-sensitive photocurrent with an anisotropy ratio as high as 0.83. Additionally, the device can function in a zero-bias photovoltaic mode, enabling a fast photoresponse and low dark current. The external quantum efficiency can reach ≈3%, which is impressive for BP-based devices. The results pave the way for the implementation of p-BP/n-InSe heterostructure as a promising candidate for future multifunctional optoelectronics and, especially, polarization-sensitive applications.

2D Metal Chalcogenides for IR Photodetection

“…Moreover, 2DMCs/BP hybrid heterostructures toward IR photodetection have been gradually reported, in which obvious polarization‐sensitive photoresponse has been demonstrated due to the anisotropic light absorption of BP. Ye et al have fabricated a hybrid heterostructure photodetector, in which WSe 2 acts as the conductive channel and the BP serves as the photogate on the top of WSe 2 .…”

“…[143] The performance not only exceeds the MoTe 2 /graphene [138] and WSe 2 /graphene/MoS 2 heterostructure [142] but also is superior to the current advanced commercial infrared photodetectors (≈10 12 Jones) requiring cryogenic cooling. [1] Moreover, 2DMCs/BP hybrid heterostructures toward IR photodetection have been gradually reported, [146,147,158] in which obvious polarization-sensitive photoresponse has been demonstrated due to the anisotropic light absorption of BP. Ye et al have fabricated a hybrid heterostructure photodetector, in which WSe 2 acts as the conductive channel and the BP serves as the photogate on the top of WSe 2 .…”

Optical and Optoelectronic Properties of Black Phosphorus and Recent Photonic and Optoelectronic Applications

“…The ultrahigh carrier mobility of graphene and suppressed Schottky barrier give rise to efficient photocurrent extraction as exemplified by the ultrahigh photoresponsivity of 3.3 × 10 3 A W −1 . The strong in‐plane anisotropy of BP can also be utilized in polarization‐dependent photodetectors . In combination with other anisotropic materials such as ReS 2 , Li et al have fabricated BP–ReS 2 heterostructure for polarized light detection, as shown in Figure c.…”

Symmetry‐Reduction Enhanced Polarization‐Sensitive Photodetection in Core–Shell SbI3/Sb2O3 van der Waals Heterostructure

“…In addition, many researchers have investigated the polarized photodetectors with BP‐based heterostructures for enhancing the device performance, particularly including the anisotropy ratio . For example, the photocurrent anisotropy ratio of polarization‐sensitive photodetector based on pure BP was 3.5, while the photocurrent anisotropy ratio of the device increased to 6 and even 10.76 by constructing the BP/ReSe 2 and BP/InSe heterostructure photodetectors, respectively . Further results indicated that fabricating heterostructure could be a desirable and effective method to improve the in‐plane anisotropy by symmetry‐reduction in low‐dimensional materials .…”

“…[6] For example, the photocurrent anisotropy ratio of polarization-sensitive photodetector based on pure BP was 3.5, [26] while the photocurrent anisotropy ratio of the device increased to 6 and even 10.76 by constructing the BP/ReSe 2 and BP/InSe heterostructure photodetectors, respectively. [27,28] Further results indicated that fabricating heterostructure could be a desirable and effective method to improve the in-plane anisotropy by symmetry-reduction in low-dimensional materials. [29][30][31] However, BP, BP-based heterostructures and numerous 2D anisotropy semiconductors have relatively narrow bandgap, and complicated optical systems are required to regulate them within the desirable short spectral range.…”