An Accurate Method for Measuring Activation Energy

TL;DR

This paper introduces a combined photoluminescence method to accurately measure activation energy, revealing a step transition in emission mechanisms and clarifying light emission origins in GaN.

Contribution

A novel approach combining excitation power and temperature dependent photoluminescence for precise activation energy measurement.

Findings

Activation energy of GaN free exciton A is 24 meV.

Identified a step transition in emission mechanisms with temperature.

Provided insights into the origin of light emission in GaN at room temperature.

Abstract

In this letter, we present an accurate method for the measurement of activation energy. This method combined the excitation power dependent photoluminescence and temperature dependent photoluminescence together to obtain activation energy. We found with increasing temperature, there is a step transition from one emission mechanism to another. This step transition gives us an accurate measurement of activation energy. Using this new method we found the activation energy of the free exciton A in a GaN thin film is 24 meV. Our result also gives a reasonable explanation of the debate of the origin of the light emission in GaN at room temperature.