Quantum emitter formation dynamics and probing of radiation induced atomic disorder in silicon

TL;DR

This study investigates the formation and properties of G-centers in silicon under proton irradiation, revealing how irradiation conditions influence defect formation, atomic disorder, and potential quantum applications.

Contribution

It provides new insights into the dynamics of G-center formation and atomic disorder in silicon under various proton fluxes, combining experimental photoluminescence and ab initio calculations.

Findings

Pulsed proton irradiation enhances G-center formation efficiency.

Narrow linewidths are preserved at moderate fluences, broadening at higher fluences.

Atomic disorder causes shifts in G-center emission due to vacancies and interstitials.

Abstract

Near infrared color centers in silicon are emerging candidates for on-chip integrated quantum emitters, optical access quantum memories and sensing. We access ensemble G color center formation dynamics and radiation-induced atomic disorder in silicon for a series of MeV proton flux conditions. Photoluminescence results reveal that the G-centers are formed more efficiently by pulsed proton irradiation than continuous wave proton irradiation. The enhanced transient excitations and dynamic annealing within nanoseconds allows optimizing the ratio of G-center formation to nonradiative defect accumulation. The G-centers preserve narrow linewidths of about 0.1 nm when they are generated by moderate pulsed proton fluences, while the linewidth broadens significantly as the pulsed proton fluence increases. This implies vacancy/interstitial clustering by overlapping collision cascades. Tracking G-center properties for a series of irradiation conditions enables sensitive probing of atomic disorder, serving as a complimentary analytical method for sensing damage accumulation. Aided by ${\it ab}$ ${\it initio}$ electronic structure calculations, we provide insight into the atomic disorder-induced inhomogeneous broadening by introducing vacancies and silicon interstitials in the vicinity of a G-center. A vacancy leads to a tensile strain and can result in either a redshift or blueshift of the G-center emission, depending on its position relative to the G-center. Meanwhile, Si interstitials lead to compressive strain, which results in a monotonic redshift. High flux and tunable ion pulses enable the exploration of fundamental dynamics of radiation-induced defects as well as methods for defect engineering and qubit synthesis for quantum information processing.