Çörekçi, S.Dugan, S.Öztürk, M. K.Çetin, S. Ş.Çakmak, M.Özçelik, S.Özbay, Ekmel2018-04-122018-04-1220160361-5235http://hdl.handle.net/11693/36890Two AlInN/AlN/GaN heterostructures with 280-nm- and 400-nm-thick AlN buffer grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and Hall-effect measurements. The symmetric (0002) plane with respect to the asymmetric (101 ¯ 2) plane in the 280-nm-thick AlN buffer has a higher crystal quality, as opposed to the 400-nm-thick buffer. The thinner buffer improves the crystallinity of both (0002) and (101 ¯ 2) planes in the GaN layers, it also provides a sizeable reduction in dislocation density of GaN. Furthermore, the lower buffer thickness leads to a good quality surface with an rms roughness of 0.30 nm and a dark spot density of 4.0 × 108 cm−2. The optical and transport properties of the AlInN/AlN/GaN structure with the relatively thin buffer are compatible with the enhancement in its structural quality, as verified by XRD and AFM results.EnglishAlInN barrierAlInN/AlN/GaN HEMTAlN bufferAtomic force microscopyDislocations (crystals)Gallium nitrideMetallorganic chemical vapor depositionOrganic chemicalsOrganometallicsSapphireVapor depositionX ray diffractionA3. metal organic chemical vapor deposition (MOCVD)Dislocation densitiesHall effect measurementSapphire substratesStructural qualitiesSemiconducting aluminum compoundsArticle10.1007/s11664-016-4536-z