Local Avalanche Photodetectors Driven by Lightning-rod Effect and Surface Plasmon Excitations

TL;DR

This paper introduces a novel 4H-SiC avalanche photodetector design that leverages lightning-rod effect and surface plasmon excitations to achieve low breakdown voltage, high detectivity, and stable operation without quenching circuits.

Contribution

The study presents a new APD architecture using micro-holes and Al nano-triangles to significantly reduce breakdown voltage and enhance detection performance in the ultraviolet spectrum.

Findings

Record low avalanche breakdown voltage of ~14.5 V

High detectivity of 7E13 Jones

Stable detection with nanosecond response time

Abstract

Sensitive avalanche photodetectors (APDs) that operate within the ultraviolet spectrum are critically required for applications in detecting fire and deep-space exploration. However, the development of such devices faces significant challenges, including high avalanche breakdown voltage, the necessity for complex quenching circuits, and thermal runaway associated with Geiger-mode avalanche operation. To mitigate these issues, we report on a 4H-SiC APD design utilizing micro-holes (MHs) structures and Al nano-triangles (NTs) to enhance surface electric field driven by strong localized surface plasmon excitations and lightning-rod effect. The device demonstrates a record low avalanche breakdown voltage of approximately 14.5 V, a high detectivity of 7E13 Jones, a nanosecond-level response time, and repeated stable detections without the requirement of a quenching circuit. Collectively, when compared with the conventional wide-bandgap-based APDs, this device achieves a reduction in avalanche breakdown voltage by an order of magnitude and exhibits a substantial increase in detectivity. Consequently, the proposed APD configuration presents a promising candidate for ultraviolet detection and integrated optoelectronic circuits.