Effect of Strain on the Band Line Up and Built in Electric Field of Strained AlGaN/GaN and InGaN/GaN Quantum Well

Abstract

One of the important parameters associated with the carrier confinement of hetero structures is their band line up. Here we have developed the relations to compute the band line up of materials Al_xGa_1-xN/GaN and In_xGa_1-xN/GaN and the effect of strain in the built in electric field. The band positions for the heterointerfaces of InxGa_1-xN/GaN and AlxGa_1-xN/GaN are calculated from equations developed, which are related with the position of the bands with the strain at the interface and are compared. Thus the strain is calculated and compared for both In_xGa_1-xN/GaN and Al_xGa_1-xN/GaN from the respective In and Ga mole fraction (Panda et al., International conference on computers and devices for communication, 2009) [1]. Due to the non-centrosymmetric structure of the hexagonal III-nitrides, spontaneous polarization exists in bulk films. In addition, when fabricating heterostructures of GaN/AlGaN or GaN/InGaN, the effect of piezoelectric polarization due to strain has to be taken into account. Both the spontaneous and piezoelectric polarization give rise to a large built-in field (Ng et al., J Electron Mater 30, 2001) [2].