Room-temperature high detectivity mid-infrared photodetectors based on black arsenic phosphorus (1705.00801v1)

Abstract: The mid-infrared (MIR) spectral range, pertaining to important applications such as molecular 'fingerprint' imaging, remote sensing, free space telecommunication and optical radar, is of particular scientific interest and technological importance. However, state-of-the-art materials for MIR detection are limited by intrinsic noise and inconvenient fabrication processes, resulting in high cost photodetectors requiring cryogenic operation. We report black arsenic-phosphorus-based long wavelength infrared photodetectors with room temperature operation up to 8.2 um, entering the second MIR atmospheric transmission window. Combined with a van der Waals heterojunction, room temperature specific detectivity higher than 4.9*10^9 Jones was obtained in the 3-5 um range. The photodetector works in a zero-bias photovoltaic mode, enabling fast photoresponse and low dark noise. Our van der Waals heterojunction photodector not only exemplify black arsenic-phosphorus as a promising candidate for MIR opto-electronic applications, but also pave the way for a general strategy to suppress 1/f noise in photonic devices.

• The paper introduces a novel room-temperature MIR photodetector design based on b-AsP, achieving detectivity >4.9×10⁹ Jones in the 3–5 μm range.
• It employs a van der Waals heterojunction with MoS₂ to significantly suppress 1/f noise and enable a zero-bias photovoltaic mode.
• The detectors demonstrate fast response (~0.54 ms) and high responsivity (15–30 mA/W), underscoring their potential for MIR imaging and sensing applications.

Room-Temperature High Detectivity Mid-Infrared Photodetectors Based on Black Arsenic Phosphorus

The paper presents a significant advancement in the field of mid-infrared (MIR) photodetectors by utilizing black arsenic phosphorus (b-AsP) as a novel material to develop devices capable of operating at room temperature with high detectivity. Traditional MIR detectors such as those based on HgCdTe alloys and group III–V materials often require complex fabrication processes and cryogenic temperatures, limiting their practical applications. This paper explores the potential of b-AsP, a two-dimensional layered material, for overcoming these limitations, marking a noteworthy contribution to the field of MIR optoelectronics.

Key Findings

The researchers successfully fabricated b-AsP photodetectors that function efficiently at room temperature, with specific detectivity values exceeding 4.9×10⁹ Jones in the 3-5 μm range. A notable achievement is the detector’s ability to operate up to 8.2 μm, entering the second MIR atmospheric window. The detectors exhibit a zero-bias photovoltaic mode, contributing to low dark noise and rapid photoresponse, which are essential for high-performance photodetection.

The paper introduces a van der Waals heterojunction approach, leveraging the integrability of 2D materials to enhance the photodetector performance, particularly by suppressing 1/f noise. This strategy allows for high energy barriers at heterojunction interfaces, reducing dark current noise. The heterostructure of b-AsP with MoS₂ serves as a demonstration, resulting in marked noise suppression and improved photodetection capabilities.

Results and Implications

The experimental results indicate a high responsivity of 15-30 mA/W across the MIR range tested, with up to 6.1% external quantum efficiency (EQE) under 3.662 μm illumination. The photodetectors achieved a quick rise and fall time of approximately 0.54 ms, making them suitable for MIR imaging applications. The demonstrated anisotropic photoresponse of b-AsP could be beneficial for applications requiring polarization-sensitive detection.

The paper suggests a pathway for future development of high-performance, room-temperature MIR photodetectors by leveraging the unique properties of b-AsP and similar materials. The research highlights the potential for large-scale synthesis and integration of b-AsP into van der Waals heterostructures to further enhance device performance.

Future Directions

Going forward, research may focus on the scale-up of b-AsP synthesis and the exploration of other 2D materials to create heterojunction photodetectors with even higher performance metrics. Additionally, the development of devices tailored for specific applications such as remote sensing and free space telecommunication could be pursued.

This work not only broadens the scope of materials available for MIR detection but also encourages the adoption of two-dimensional material systems in practical optoelectronic applications. The potential for room-temperature operation combined with high detectivity and low noise sets a benchmark for future research in the field, promising advancements in MIR technology and its applications.