Thermal activation energy on InGaAsN/GaAs single quantum well

• Grant number: 11/14127-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2011
• End date: December 31, 2012
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Américo Sheitiro Tabata
• Grantee: Jonatas da Silva Cavalcante
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

In this work we will intend to study the annealing effects on InxGa1-xAs0, 984N0,016/GaAs quantum wells, more specifically, on their thermal activation energy for both majority and minority carriers. Annealing is required in these kinds of samples, in order to improve their crystalline characteristics. However, this procedure can lead to a change in the confining profile potential due to, mainly, the diffusion of element Indium. We will focus our studies on the changes on the activation energy due to the change on the potential profile. In a simple theoretical model the calculation of thermal activation energy is done considering the existence of two independent populations of electron-hole pairs, one on the barrier and another inside the quantum well. These electron-hole pairs are photo created by laser excitation in the barrier. Then, part of this population is transferred to the quantum well and part recombines not radiatively in the barrier. Inside the quantum well part of the population also recombines radiatively (the photoluminescence) and part is thermally emitted to the barrier. Writing a rate equation for the populations in the barrier and in the quantum well and resolving them simultaneously, you get an equation involving the photoluminescence emission intensity as a function of the temperature and the thermal activation energy. So, adjusting our theoretical results with our experimental data we can determine the activation energy of the carriers escape from the quantum well. We should point out that knowledge of thermal activation energy is essential to determine the applicability at high temperatures and estimating the yield in devices based on this material. (AU)