Systematic characterization of nanoscale $h$-BN quantum sensor spots created by helium-ion microscopy

TL;DR

This study systematically characterizes nanoscale $V_B^-$ defect spots in $h$-BN created by helium-ion microscopy, providing guidelines to optimize their performance as quantum sensors.

Contribution

It offers a detailed analysis of how helium-ion dose, flake thickness, and substrate affect defect properties, advancing the controlled fabrication of $h$-BN quantum sensors.

Findings

Optimal creation conditions for $V_B^-$ defects identified

Monte Carlo calculations successfully interpret physical results

Guidelines established for maximizing sensor sensitivity and localization

Abstract

The nanosized boron vacancy ($V_\mathrm{B}^-$) defect spot in hexagonal boron nitride ($h$-BN) is promising for a local magnetic field quantum sensor. One of its advantages is that a helium-ion microscope can make a spot at any location in an $h$-BN flake with nanometer accuracy. In this study, we investigate the properties of the created nanosized $V_\mathrm{B}^-$ defect spots by systematically varying three conditions: the helium-ion dose, the thickness of the $h$-BN flakes, and the substrate on which the $h$-BN flakes are attached. The physical background of the results obtained is successfully interpreted using Monte Carlo calculations. From the findings obtained here, a guideline for their optimal creation conditions is obtained to maximize its performance as a quantum sensor concerning sensitivity and localization.