Room-temperature photo-chromism of silicon vacancy centers in CVD diamond

TL;DR

This study demonstrates room-temperature control and observation of charge state interconversion in silicon-vacancy centers in diamond, revealing mechanisms crucial for quantum sensing and information applications.

Contribution

It provides the first detailed room-temperature analysis of charge dynamics in SiV centers using confocal microscopy and electric fields.

Findings

Charge interconversion between SiV0, SiV-, and SiV2- observed at room temperature.

Two-step hole capture process leading to SiV0 formation identified.

Red illumination induces reversible charge state transformations.

Abstract

The silicon-vacancy (SiV) center in diamond is typically found in three stable charge states, SiV0, SiV- and SiV2-, but studying the processes leading to their formation is challenging, especially at room temperature, due to their starkly different photo-luminescence rates. Here, we use confocal fluorescence microscopy to activate and probe charge interconversion between all three charge states under ambient conditions. In particular, we witness the formation of SiV0 via the two-step capture of diffusing, photo-generated holes, a process we expose both through direct SiV0 fluorescence measurements at low temperatures and confocal microscopy observations in the presence of externally applied electric fields. Further, we show that continuous red illumination induces the converse process, first transforming SiV0 into SiV-, then into SiV2-. Our results shed light on the charge dynamics of SiV and promise opportunities for nanoscale sensing and quantum information processing.