Optical Properties and Modal Gain of InGaN Quantum Dot Stacks

TL;DR

This study investigates the optical properties and modal gain of stacked InGaN quantum dot layers, demonstrating enhanced photoluminescence and potential for optical device integration.

Contribution

It provides new insights into the optical behavior of stacked quantum dot layers and compares their performance to single-layer structures.

Findings

Superlinear increase in photoluminescence with more quantum dot layers

Quantum dot character confirmed by microphotoluminescence at various temperatures

Modal gain and threshold power density analyzed for device applications

Abstract

We present investigations of the optical properties of stacked InGaN quantum dot layers and demonstrate their advantage over single quantum dot layer structures. Measurements were performed on structures containing a single layer with quantum dots or threefold stacked quantum dot layers, respectively. A superlinear increase of the quantum dot related photoluminescence is detected with increasing number of quantum dot layers while other relevant GaN related spectral features are much less intensive when compared to the photoluminescence of a single quantum dot layer. The quantum dot character of the active material is verified by microphotoluminescence experiments at different temperatures. For the possible integration within optical devices in the future the threshold power density was investigated as well as the modal gain by using the variable stripe length method.