Distinguishing cubic and hexagonal phases within InGaN/GaN microstructures using electron energy loss spectroscopy
نویسندگان
چکیده
3D InGaN/GaN microstructures grown by metal organic vapor phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) have been extensively studied using a range of electron microscopy techniques. The growth of material by MBE has led to the growth of cubic GaN material. The changes in these crystal phases has been investigated by Electron Energy Loss Spectroscopy, where the variations in the fine structure of the N K-edge shows a clear difference allowing the mapping of the phases to take place. GaN layers grown for light emitting devices sometimes have cubic inclusions in the normally hexagonal wurtzite structures, which can influence the device electronic properties. Differences in the fine structure of the N K-edge between cubic and hexagonal material in electron energy loss spectra are used to map cubic and hexagonal regions in a GaN/InGaN microcolumnar device. The method of mapping is explained, and the factors limiting spatial resolution are discussed.
منابع مشابه
Stabilization of 4H hexagonal phase in gold nanoribbons
Gold, silver, platinum and palladium typically crystallize with the face-centred cubic structure. Here we report the high-yield solution synthesis of gold nanoribbons in the 4H hexagonal polytype, a previously unreported metastable phase of gold. These gold nanoribbons undergo a phase transition from the original 4H hexagonal to face-centred cubic structure on ligand exchange under ambient cond...
متن کاملCharacterization of InGaN/GaN quantum well growth using monochromated valence electron energy loss spectroscopy
متن کامل
The Influence of Phonon Emission on Electron Transport in Hexagonal and Cubic Gallium Nitride
Electron transport characteristics of GaN crystals in high electric fields are shown to be essentially influenced by different optical phonon modes inherent to the hexagonal and cubic phases of these compound crystals. Additional optical phonon modes (≈ 26 meV) competing with the higher-energy ones (≈ 92 meV) in hexagonal GaN, together with the low-lying satellite valley (Γ3), dramatically redu...
متن کاملZincblende and wurtzite phases in InN epilayers and their respective band transitions
Zincblende and wurtzite phases of InN are found in InN epilayers deposited by molecular beam epitaxy on GaN buffers which were grown by metal organic chemical vapor deposition. Valence electron energy loss spectroscopy (VEELS) was applied to determine band transitions in both phases of InN. GaN buffer layers were used as VEELS reference. The chemistry and crystalline structure of the observed a...
متن کاملElectron spectroscopy imaging to study ELNES at a nanoscale.
Series of energy-filtered TEM images have been acquired with very narrow energy slit using a post-column energy filter. This allowed us to reconstruct spectra with an energy resolution estimated to 2 eV, and a spatial resolution in the order of 0.5 nm. In that way, fine structures of the N-K edge in AlN/GaN heterostructures have been investigated and compared to EELS spectra. The fine structure...
متن کامل