Improving thermal stability of InGaN quantum wells by doping of GaN barrier layers

Thermal instability of InxGa1-x N quantum wells (QWs) is an obstacle to construct efficient blue and green LEDs and laser diodes. Structural degradation of QWs with indium content above 15% becomes severe at temperatures above 930 degrees C leading to formation of extended non-radiative areas within the active region. Our previous studies (Smalc-Koziorowska, 2021) indicated a relationship between the degradation process and metal vacancies present in the layers adjacent to the QWs. In this work, we show a method to overcome this problem by using heavy Si doping of the GaN barrier layers. In particular, such barrier layer grown on the top of n-type GaN layer below the InGaN QWs can act as a diffusion barrier for vacancies. The presence of silicon atoms increases the energy barrier for gallium vacancies migration. This effectively reduces possibility of diffusion of gallium vacancies from the n-type layer to the active region. As a result, improved thermal stability of QWs was achieved and significant degradation was not observed up to temperatures of 980 degrees C in comparison to 930 degrees C for the undoped structure. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The thermal instability of InxGa1-xN quantum wells (QWs) hinders the construction of efficient blue and green LEDs and laser diodes. In this study, a method to overcome this problem by heavy Si doping of the GaN barrier layers is presented. The presence of silicon atoms increases the energy barrier for gallium vacancies migration, effectively reducing the possibility of diffusion of gallium vacancies. As a result, improved thermal stability of QWs was achieved and significant degradation was not observed up to temperatures of 980 degrees C.