Properties of AlGaN/GaN heterostructures with double GaN buffer layer for HFET fabrication

In this work, influence of two step grow process and application of AlN inter layer on morphological, optical and electrical properties of nitrides heterostructures is investigated. application of double buffer gallium nitride in AlGaN/GaN heterostructure improved optical quality of layers observed in PL measurements. Application of multi step growth process did not change significantly morphology properties of the layers. The maximal value of Hall carrier concentration was observed for sample with double GaN layer. The highest Hall mobility of two dimensional gas at 300 K was obtained for structure with double GaN buffer layer and with additional aluminium nitride interlayer. (authors)