Influence of nanostructuring on silicon vacancy center spins in diamond pillars

TL;DR

This study investigates how nanostructuring affects the spin properties and population lifetimes of silicon vacancy centers in diamond pillars, revealing that size, substrate properties, and fabrication methods significantly influence their quantum characteristics.

Contribution

The paper provides new insights into how the transition from bulk to nano-scale structures impacts silicon vacancy center properties, including population lifetimes and inhomogeneous linewidths.

Findings

Population lifetimes vary with pillar size and fabrication methods.

Small structures may extend lifetimes due to restricted vibrational modes.

Surface damage and lattice imperfections reduce lifetimes in tiny structures.

Abstract

Color centers in diamond micro and nano structures are under investigation for a plethora of applications. However, obtaining high quality color centers in small structures is challenging, and little is known about how properties such as spin population lifetimes change during the transition from bulk to micro and nano structures. In this manuscript, we studied various ways to prepare diamond samples containing silicon vacancy centers and measured how population lifetimes of orbital states change in pillars as we varied their dimensions from approximately 1 $\mu$m to 120 nm. We also researched the influence of the properties of the diamond substrate and the implantation and annealing methods on the silicon vacancy inhomogeneous linewidth and orbital lifetime. Our measurements show that nominally identical diamond samples can display significantly distinct inhomogeneous broadening. We observed weak indications that restricted vibrational modes in small structures may extend population lifetimes. However, imperfections in the crystal lattice or surface damage caused by etching reduce population lifetimes, especially in the smallest structures.