Review of germanium-silicon single-photon avalanche diodes

TL;DR

This paper reviews the development of germanium-silicon single-photon avalanche diodes (SPADs) for shortwave infrared detection, highlighting progress from cryogenic to room temperature operation and exploring future applications.

Contribution

It provides a comprehensive overview of GeSi SPAD advancements, emphasizing recent room temperature demonstrations and potential new uses.

Findings

First cryogenic GeSi SPAD demonstrated in 2011

Recent room temperature GeSi SPAD achieved in 2024

Potential applications in optical sensing and imaging

Abstract

While it took about a decade for a germanium (Ge) thin film grown on a silicon (Si) substrate to be successfully applied as a detector material for high-speed optical fiber communication application, it took about another decade to further expand its usage as a sensor material for active optical sensing and imaging applications. In this paper, we shall review the progress of a shortwave infrared (SWIR) single-photon detection (SPD) with germanium-silicon (GeSi) single-photon avalanche diode (SPAD), ranging from the first demonstration at cryogenic temperature (Z. Lu et al., 2011) to the recent demonstration at room temperature (N. Na et al, 2024). Potential new applications will also be discussed.