Photoreflectance ͑PR͒ and contactless electroreflectance ͑CER͒ spectroscopies have been applied to study optical transitions in undoped and Si-doped AlGaN / GaN heterostructures at room temperature. Spectral features related to excitonic and band-to-band absorptions in GaN layer and band-to-band absorption in AlGaN layer have been resolved and analyzed. In addition, a broad spectral feature related to two-dimensional electron gas has been observed for the Si-doped heterostructure. It has been found that some of the mentioned optical transitions are not observed in CER spectra whereas they are very strong in PR spectra. This phenomenon is associated with different mechanisms of the modulation of built-in electric field in the investigated structure. A combination of PR and CER gives the possibility of a richer interpretation of both PR and CER spectra.
The epitaxial growth of InN by the open tube flow method using the interaction of InCl3 and NH3 is discussed. The influence of various technological parameters on the process and structure perfection of the epitaxial layers, grown on the single crystal (0001)‐oriented sapphire substrates is considered. The main kinetic dependences of the process are plotted and discussed.
InN epitaxial layers were mosaic and n‐type with electron concentration 2 · 1020–8 · 1021 cm−3 and mobilities 50‐35 cm2/V · s, respectively.
The structure, morphology and optical properties of GaN films deposited by metalorganic vapour phase epitaxy (MOVPE) on alternative substrates: ZnO, NdGaO, YSZ (yttria stabilized zirconia). Scanning electron microscopy, X‐ray diffraction and photoluminescence were used for the epitaxial layers characterisation. The obtained results have been compared to those of GaN layers grown on c‐plane sapphire substrates. It was established that the most important step towards the realisation of device quality GaN material on alternative substrates is the first stage of the growth process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.