  Nanoscale strain has emerged as a powerful tool for controlling single-photon
emitters (SPEs) in atomically thin transition metal dichalcogenides (TMDCs)(1,
2). However, quantum emitters in monolayer TMDCs are typically unstable in
ambient conditions. Multilayer two-dimensional (2D) TMDCs could be a solution,
but they suffer from low quantum efficiency, resulting in low brightness of the
SPEs. Here, we report the deterministic spatial localization of strain-induced
single-photon emitters in multilayer GaSe by nanopillar arrays. The
strain-controlled quantum confinement effect introduces well-isolated
sub-bandgap photoluminescence and corresponding suppression of the broad band
edge photoluminescence. Clear photon-antibunching behavior is observed from the
quantum dot-like GaSe sub-bandgap exciton emission at 3.5 Kelvin. The
strain-dependent confinement potential and the brightness are found to be
strongly correlated, suggesting a promising route for tuning and controlling
SPEs. The comprehensive investigations of strain-engineered GaSe SPEs provide a
solid foundation for the development of 2D devices for quantum photonic
technologies.
