Toward Single-Photon Detection with Superconducting Niobium Diselenide Nanowires

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Superconducting nanowire single-photon detectors (SNSPDs) are critical for quantum information science.
• Few-layer transition metal dichalcogenides (TMDs) offer unique electronic properties but face fabrication challenges.

Purpose of the Study:

• To fabricate and characterize superconducting nanowire photodetectors based on few-layer NbSe2.
• To demonstrate single-photon sensitivity in these novel detectors.
• To optimize device geometry for enhanced performance.

Main Methods:

• Top-down fabrication of hexagonal boron nitride (hBN)-encapsulated few-layer NbSe2 nanowires.
• Low-temperature transport measurements to confirm superconducting properties.
• Optical characterization of responsivity, recovery time, timing jitter, and detection efficiency.

Main Results:

• Fabricated NbSe2 nanowires preserved superconducting properties with low contact resistance (~30 Ω at 4 K).
• Meandered NbSe2 nanowires achieved high responsivity (up to 4.9 × 10^4 V/W) from 650-1550 nm.
• Demonstrated single-photon sensitivity at 1100 nm with a detection efficiency of ~0.01% and a recovery time of 135 ns.

Conclusions:

• hBN-encapsulated few-layer NbSe2 is a viable material for superconducting nanowire single-photon detectors.
• Meandered geometry enhances detector performance, particularly responsivity.
• These detectors show promise for various optical sensing applications requiring high sensitivity.