Size-enhanced, coherent photoluminescence from CdS-ZnO nanocomposite thin film

TL;DR

This study demonstrates that a CdS-ZnO nanocomposite thin film exhibits enhanced, coherent photoluminescence, with potential applications in quantum information processing and lasing, due to its unique optical properties and nanostructure.

Contribution

It introduces a novel CdS-ZnO nanocomposite thin film with enhanced, coherent photoluminescence and characterizes its optical coherence properties for the first time.

Findings

Photoluminescence from the nanocomposite is significantly higher than from pure CdS or ZnO.

The nanocomposite exhibits a single, sharp optical absorption edge.

The emitted photoluminescence shows significant spatio-temporal coherence.

Abstract

We show that the photoluminescence emitted from a dense, two-component ensemble of quantum dots is significantly higher than that from quantum dots of either of the two pure systems (CdS and ZnO). The semiconductor nanocomposite, in which the characteristic grain size of each species was 2-3 nm, was deposited directly on Si wafers by high-pressure magnetron sputtering. It exhibits a single, relatively sharp optical absorption edge. Further, using the classical Young's double slit experiment we show - possibly for the first time - that the emitted photoluminescence has significant spatio-temporal coherence, a fact that would be crucial for their use in quantum information processing as well as for lasing action from light-emitting particles.