Plasmon-Driven Hot Electron Transfer at Atomically Sharp Metal-Semiconductor Nanojunctions

TL;DR

This paper presents a novel monolithic Al-Ge heterostructure device that enables detailed study and control of plasmon-induced hot electron transfer at an atomically sharp metal-semiconductor interface, advancing energy-harvesting applications.

Contribution

It introduces a new platform for examining hot electron transfer at metal-semiconductor nanojunctions with electrostatic control of the Schottky barrier.

Findings

Demonstrated control of hot electron injection energy distribution.

Achieved electrostatic tuning of Schottky barrier height.

Observed negative differential resistance due to interband electron transfer.

Abstract

Recent advances in guiding and localizing light at the nanoscale exposed the enormous potential of ultra-scaled plasmonic devices. In this context, the decay of surface plasmons to hot carriers triggers a variety of applications in boosting the efficiency of energy-harvesting, photo-catalysis and photo-detection. However, a detailed understanding of plasmonic hot carrier generation and particularly the transfer at metal-semiconductor interfaces is still elusive. In this paper, we introduce a monolithic metal-semiconductor (Al-Ge) heterostructure device, providing a platform to examine surface plasmon decay and hot electron transfer at an atomically sharp Schottky nanojunction. The gated metal-semiconductor heterojunction device features electrostatic control of the Schottky barrier height at the Al-Ge interface, enabling hot electron filtering. The ability of momentum matching and to control the energy distribution of plasmon-driven hot electron injection is demonstrated by controlling the interband electron transfer in Ge leading to negative differential resistance.