Structural fluctuations in Nitride Heterostructures :Consequences for Localisation and device performance

摘要

Nitride heterostructures based on InN, GaN and AlN can span a wide range ofband gaps and can generate very large interface fields due to their large polarisation charges.These structures have found applications as light emitters (InGaN/GaN) and electronicdevices (AlGaN/GaN). The properties mentioned above (large band gap variations andpolarisation fields) also imply that structural fluctuations (alloy disorder, interface roughness,etc.) can cause large degrees of electronic state localisation. In this work, we examine atypical light emitter structure with regards to electron localisation effects arising out of alloydisorder and interface roughness. We then present an analysis of these results and corelatewith behaviour of density of states in the structure and a new measure of degree of localisationwe define.