Time-Resolved Spectroscopy of Single Excitons Bound to Pairs of Te Isoelectronic Impurity Centers in ZnSe

TL;DR

This study investigates single excitons bound to tellurium pairs in ZnSe using time-resolved photoluminescence, revealing their unique optical properties and confirming their nature through ab-initio calculations.

Contribution

It provides the first detailed experimental and theoretical analysis of excitons bound to Te pairs in ZnSe, highlighting their fine-structure and photon emission characteristics.

Findings

Observation of anti-bunched photon emission from Te2 centers

Identification of doublet polarization along specific crystallographic directions

Clarification of dark states' role in exciton spin relaxation

Abstract

Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence (PL) spectroscopy. Resolution-limited peaks with an ultra-low spatial density originate in the recombination of excitons deeply bound to isolated nearest-neighbor isoelectronic Te pairs (Te2). This interpretation is confirmed by ab-initio calculations. The peaks reveal anti-bunched photon emission and a doublet structure polarized along [110] and [-110]. We analyze the time-resolved PL decay to clarify the role of the dark states in the spin relaxation and radiative recombination of single fine-structure split excitons.