Silicon single-photon detector achieving over 84% photon detection efficiency with flexible operation modes

TL;DR

This paper reports a silicon single-photon detector with over 84% efficiency at 785 nm, supporting multiple operation modes, achieved through innovative design and fabrication techniques for high performance.

Contribution

The authors developed a high-efficiency Si SPD with a thick-junction avalanche diode and versatile operation modes, advancing detector performance and application flexibility.

Findings

Achieved 84.4% PDE at 785 nm in free-running mode

Dark count rate of 260 cps at 268 K

Afterpulse probability of 2.9%

Abstract

Silicon single-photon detectors (Si SPDs) play a crucial role in detecting single photons in the visible spectrum. For various applications, photon detection efficiency (PDE) is the most critical characteristic for effectively collecting photons. Here, we present a Si SPD with a remarkable PDE of up to 84.4% at 785 nm, supporting multiple operation modes. We design and fabricate a thick-junction Si single-photon avalanche diode (SPAD) that enhances the avalanche probability through a backside-illumination structure, while minimizing noise through the design of a doping-compensated avalanche region. To maximize PDE, we implement a readout circuit with a 50 V quenching voltage, enabling operation in free-running, gating, or hybrid modes. The SPAD, along with its readout circuits and affiliated circuits, is integrated into a compact SPD module. In free-running mode, the module achieves a maximum PDE of 84.4%, with a dark count rate of 260 cps, and an afterpulse probability of 2.9% at 268 K. This work provides a practical solution for applications requiring ultra-high-efficiency Si SPD with multiple operation modes.