InGaN/GaN Heterojunction Structures Fabricated by MBE (original) (raw)
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Growth of InGaN Films by MBE at the Growth Temperature of GaN
MRS Proceedings, 1995
ABSTRACTWe report the growth of InGaN alloys over practically the entire composition range at the growth temperature of GaN (700–800 °C) by MBE. We found that when the grown films are thick (> 0.3 μm), incorporation of more than about 30% indium results in phase separation of InN, which is consistent with spinodal decomposition. On the other hand we discovered that such phase separation is absent in thin InGaN films ( < 600Å) grown as GaN/InGaN/GaN heterostructures. In such configurations we were able to incorporate up to 81% In, which is the highest yet reported.
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2002
Preliminary results of growth of thin diamond film in a recently installed 3 kW capacity microwave plasma activated CVD (MW-PACVD) system are being reported. The films were deposited on Si (100) substrate at 850 • C using methane and hydrogen mixture at 1·5 kW MW power. The grown polycrystalline films were characterized by micro-Raman, transmission electron microscope (TEM), spectrophotometer and atomic force microscope (AFM). The results were compared with that of a thicker diamond film grown elsewhere in a same make MW-PACVD system at relatively higher power densities. The presence of a sharp Raman peak at 1332 cm −1 confirmed the growth of diamond, and transmission spectra showed typical diamond film characteristics in both the samples. Typical twin bands and also a quintuplet twinned crystal were observed in TEM, further it was found that the twinned region in thin sample composed of very fine platelet like structure.
Self-assembled InGaN quantum dots grown by molecular-beam epitaxy
Applied Physics Letters, 2000
Self-assembled InGaN islands were grown by molecular-beam epitaxy on GaN, following a Stranski-Krastanow growth mode. Atomic force microscopy revealed that their dimensions were small enough to expect zero-dimensional quantum effects: the islands were typically 27 nm wide and 2.9 nm high. Strong blue-violet photoluminescence of the dots is observed, persisting up to room temperature. The temperature dependence of the photoluminescence is analyzed and compared to that of InGaN quantum well and bulk samples.
Japanese Journal of Applied Physics, 2013
The growth of InGaN with intermediate In compositions on GaN/sapphire template and AlN/Si(111) substrate has been comparatively studied. By using an metalorganic vapor phase epitaxy (MOVPE) system with a horizontal reactor, InGaN films are grown at a temperature of 600-800 C in the pressure of 150 Torr. By optimizing growth temperature and trimethylindium=ðtrimethylindium þ triethylgalliumÞ molar ratio, single crystalline In x Ga 1Àx N with x ¼ 0{1 are successfully grown on both substrates. The films grown at a relatively high temperature (!700 C) with In compositions of 0.3 or less show phase separation when their thickness exceeds a critical value (0.25-0.4 m), while the samples grown at 600 C with In compositions of 0.35-0.5 show no phase separation even if the thickness is increased to 0.7 m. To evaluate the crystalline quality of grown films, FWHM of X-ray rocking curve (XRC) for InGaN(0002), tilt, is measured. There is no marked difference in tilt data between films grown on GaN/-Al 2 O 3 (0001) and AlN/Si(111). For the samples grown at 600 C with In contents of 0.35-0.5, tilt data are drastically increased and widely scattered suggesting the existence of important unknown parameters that govern crystalline quality of InGaN grown at a relatively low temperature.
Effect of growth interrupt and growth rate on MOVPE-grown InGaN/GaN MQW structures
Journal of Crystal Growth, 2003
InGaN/GaN multiple quantum wells (MQWs) were grown by metalorganic vapor phase epitaxy to quantify the influence of various growth parameters on the optical properties and on the In incorporation. Decreasing the group III flux results in improved room temperature photoluminescence intensity. Introduction of 5 and 10 s interrupts at the MQW interfaces gives rise to loss of In. High temperature capping of MQWs with GaN:Mg produces blackening of the layers for an In content exceeding 12%, due to formation of In platelets. r . Multiple quantum wells; B1. InGaN 0022-0248/03/$ -see front matter r 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 2 -0 2 4 8 ( 0 2 ) 0 1 8 4 7 -X
Journal of Crystal Growth, 1998
InGaN/GaN single and multi quantum wells have been grown by metal-organic chemical vapor deposition, varying the growth rate of well and barrier layers as well as the Si-doping of the GaN barriers. Separately, the effect of these growth parameters on the surface morphology of thin GaN and InGaN layers grown under the same conditions had been studied. The surface morphology of the layers strongly influenced the structural properties of the multi quantum wells. The optical properties seemed to be less affected by the observed layer thickness fluctuations in the 200-500 nm range rather than by variations in the indium composition on a shorter length scale.
Secrets of GaN substrates properties for high luminousity of InGaN quantum wells
Light-Emitting Diodes: Research, Manufacturing, and Applications XII, 2008
Violet and blue Laser diodes, as well as highly efficient high-power Light Emitting Diodes (including any UV emitters) can be constructed using low-dislocation-density freestanding GaN substrates, either produced as thick HVPE layers on foreign substrates, or using direct methods of crystallization as ammonothermal one or high pressure growth from the nitrogen solution in gallium. This paper shows some of the most most important issues concerning application of such substrates. The first issue is the choice of the substrate thickness influencing the accommodation of strain, cracking and bowing of the samples. In this point, a new way of prestressing the substrate by lateral patterning will be presented. The second issue is the surface preparation either by mechanical polishing and reactive ion etching, or mechano-chemical polishing, in particular, a distribution of defects revealed by chemical etching will be discussed. Finally, the problem of substrate misorientation influencing the further morphology and indium incorporation into InGaN quantum wells will be shown. For higher misorientation of the substrates, the incorporation of indium decreases , but at the same time, the fluctuations of indium increase giving blue-shifted, weaker and broader photoluminescence peaks.