Avalanche amplification of a single exciton in a semiconductor nanowire

TL;DR

This paper demonstrates that a single exciton in a semiconductor nanowire can be amplified through avalanche multiplication, enabling efficient electrical detection with far fewer excitation events, advancing quantum information technologies.

Contribution

The study introduces a method to amplify carriers from a single exciton in a nanowire avalanche photodiode, significantly reducing the number of events needed for electrical detection.

Findings

Carrier multiplication factor exceeds 10^4

Reduces excitation events for detection by four orders of magnitude

Enables potential for single-shot electrical read-out of quantum states

Abstract

Interfacing single photons and electrons is a crucial ingredient for sharing quantum information between remote solid-state qubits. Semiconductor nanowires offer the unique possibility to combine optical quantum dots with avalanche photodiodes, thus enabling the conversion of an incoming single photon into a macroscopic current for efficient electrical detection. Currently, millions of excitation events are required to perform electrical read-out of an exciton qubit state. Here we demonstrate multiplication of carriers from only a single exciton generated in a quantum dot after tunneling into a nanowire avalanche photodiode. Due to the large amplification of both electrons and holes (> 10^4), we reduce by four orders of magnitude the number of excitation events required to electrically detect a single exciton generated in a quantum dot. This work represents a significant step towards single-shot electrical read-out and offers a new functionality for on-chip quantum information circuits.