Core-shell multi-quantum wells in ZnO / ZnMgO nanowires with high optical efficiency at room temperature

TL;DR

This paper demonstrates that ZnO/ZnMgO core-shell quantum well nanowires grown by metal organic vapour phase epitaxy can achieve high optical efficiencies at room temperature, crucial for nanowire-based light-emitting devices.

Contribution

It introduces a method to grow high-efficiency quantum well heterostructures in nanowires with controlled Mg concentration to optimize optical performance at room temperature.

Findings

Lower Mg concentration (x=0.15) retains 54% of low-temperature luminescence at room temperature.

Higher Mg concentration (x=0.30) results in only 2% retention at room temperature.

Misfit dislocations form at higher Mg concentrations, affecting luminescence efficiency.

Abstract

Nanowire-based light-emitting devices require multi-quantum well heterostructures with high room temperature optical efficiencies. We demonstrate that such efficiencies can be attained through the use of ZnO/Zn(1-x)MgxO core shell quantum well heterostructures grown by metal organic vapour phase epitaxy. Varying the barrier Mg concentration from x=0.15 to x=0.3 leads to the formation of misfit induced dislocations in the multi quantum wells. Correlatively, temperature dependant photoluminescence reveals that the radial well luminescence intensity decreases much less rapidly with increasing temperature for the lower Mg concentration. Indeed, about 54% of the 10K intensity is retained at room temperature with x=0.15, against 2% with x=0.30. Those results open the way to the realization of high optical efficiency nanowire-based light emitting diodes.