Spelling suggestions: "subject:"epitaxial""
171 |
Epitaxial growth by monolayer restricted galvanic displacementVasilic, Rastko. January 2006 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Department of Materials Science, 2006. / Includes bibliographical references.
|
172 |
Growth and characterization of III-V compound semiconductor materials for use in novel MODFET structures and related devicesSchulte, Donald W. 27 November 1995 (has links)
Graduation date: 1996
|
173 |
Preliminary Results of InGaAsN/GaAs Quantum-well laser Diodes Emitting towards 1.3 µmWang, S.Z., Yoon, Soon Fatt 01 1900 (has links)
GaAs-based nitride is found to be sensitive to growth conditions and ex-situ annealing processes. The critical thickness is almost one order thicker than the theoretical prediction by force balance model. The growth process could be sped up by the nitrogen incorporation itself, while the nitrogen incorporation could be affected by Beryllium doping. The incorporated nitrogen atoms partly occupy substitutional sites for Arsenic. Some nitrogen atoms are at interstitial sites. Annealing could drastically increase the optical quality of GaAs-based nitrides. As an end of this paper, some preliminary results of InGaAsN/GaAsN/AlGaAs laser diodes are also presented. / Singapore-MIT Alliance (SMA)
|
174 |
InGaAsN/GaAs Quantum-well Laser DiodesWang, S.Z., Yoon, Soon Fatt 01 1900 (has links)
GaAs-based InGaAsN/GaAs quantum well is found to be very sensitive to growth conditions and ex-situ annealing processes. Annealing could drastically increase the optical quality of GaAs-based InGaAsN/GaAs quantum well. As an end of this paper, some results on InGaAsN/GaAsN/AlGaAs laser diodes are also presented. / Singapore-MIT Alliance (SMA)
|
175 |
Molecular Beam Epitaxy of Ga(In)AsN/GaAs Quantum Wells towards 1.3µm and 1.55µmWang, S.Z., Yoon, Soon Fatt, Ng, Teck Khim, Loke, W.K., Fan, W.J. 01 1900 (has links)
In this article, we report an attempt of extending the InGaAsN materials towards 1.3µm and 1.55µm wavelength. All these InGaAsN samples are grown in a plasma-assisted solid-source molecular-beam epitaxy (SS-MBE) system. Our experiments revealed that the nitrides could be grown with both direct nitrogen beam and dispersive nitrogen. The nitrogen incorporation rate could be reduced by the presence of indium flux. The interaction between nitrogen and indium might lead to 3D growth mode and growth dynamics. It is proved that the increasing growth rate reduces the nitrogen incorporation efficiency. The data for nitrogen sticking coefficient are somewhat contradictive. The growth with dispersive nitrogen source causes the improvement of material quality. Fixed indium flux is a better way for the wavelength control. Also, we report some growth optimization work for better PL property and the annealing effect on the samples. Literature is sometimes reviewed for comparison. / Singapore-MIT Alliance (SMA)
|
176 |
Heteroepitaxial growth of InN and InGaN alloys on GaN(0001) by molecular beam epitaxyLiu, Ying, January 2005 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
|
177 |
Design and fabrication of long wavelength vertical cavity lasers on GaAs substratesMarcks von Würtemberg, Rickard January 2008 (has links)
Vertical cavity surface emitting lasers (VCSELs) are today a commodity on the short wavelength laser market due to the ease with which they are manufactured. Much effort has in the last decade been directed towards making long wavelength VCSELs as successful in the marketplace. This has not been achieved due to the much more difficult fabrication technologies needed for realising high performance long wavelength VCSELs. At one point, GaInNAs quantum wells gain regions grown on GaAs substrates seemed to be the solution as it enabled all-epitaxial VCSELs that could make use of high contrast AlGaAs-based distributed Bragg reflectors (DBRs) as mirrors and lateral selective oxidation for optical and electrical confinement, thereby mimicking the successful design of short wavelength VCSELs. Although very good device results were achieved, reproducible and reliable epitaxial growth of GaInNAs quantum wells proved difficult and the technology has not made its way into high-volume production. Other approaches to the manufacturing and material problems have been to combine mature InP-based gain regions with high contrast AlGaAs-based DBRs by wafer fusion or with high contrast dielectric DBRs. Commonly, a patterned tunnel junction provides the electrical confinement in these VCSELs. Excellent performance has been achieved in this way but the fabrication process is difficult. In this work, we have employed high strain InGaAs quantum wells along with large detuning between the gain peak and the emission wavelength to realize GaAs-based long wavelength VCSELs. All-epitaxial VCSELs with AlGaAs-based DBRs and lateral oxidation confinement were fabricated and evaluated. The efficiency of these VCSELs was limited due to the optical absorption in the doped DBRs. To improve the efficiency and manufacturability, two novel optical and electrical confinement schemes based on epitaxial regrowth of current blocking layers were developed. The first scheme is based on a single regrowth step and requires very precise processing. This scheme was therefore not developed beyond the first generation but single mode power of 0.3 mW at low temperature, -10ºC, was achieved. The second scheme is based on two epitaxial regrowth steps and does not require as precise processing. Several generations of this design were manufactured and resulted in record high power of 8 mW at low temperature, 5ºC, and more than 3 mW at high temperature, 85ºC. Single mode power was more modest with 1.5 mW at low temperature and 0.8 mW at high temperature, comparable to the performance of the single mode lateral oxidation confined VCSELs. The reason for the modest single mode power was found to be a non-optimal cavity shape after the second regrowth that leads to poor lateral overlap between the gain in the quantum wells and the intensity of the optical field. / QC 20100825
|
178 |
Structural and electrical properties of epitaxial graphene nanoribbonsBryan, Sarah Elizabeth 14 March 2013 (has links)
The objective of this research was to perform a systematic investigation of the unique structural and electrical properties of epitaxial graphene at the nanoscale. As the semiconductor industry faces increasing challenges in the production of integrated circuits, due to process complexity and scaling limitations, new materials research has come to the forefront of both science and engineering disciplines. Graphene, an atomically-thin sheet of carbon, was examined as a material which may replace or become integrated with silicon nanoelectronics. Specifically, this research was focused on epitaxial graphene produced on silicon carbide. This material system, as opposed to other types of graphene, holds great promise for large-scale manufacturing, and is therefore of wide interest to the academic and industrial community.
In this work, high-quality epitaxial graphene production was optimized, followed by the process development necessary to fabricate epitaxial graphene nanoribbon transistors for electrical characterization. The structural and electrical transport properties of the nanoribbons were elucidated through a series of distinct experiments. First, the size-dependent conductivity of epitaxial graphene at the nanoscale was investigated. Next, the alleviation of the detrimental effects revealed during the size-dependent conductivity study was achieved through the selective functionalization of graphene with hydrogen. Finally, two techniques were developed to allow for the complementary doping of epitaxial graphene. All of the experiments presented herein reveal new and important aspects of epitaxial graphene at the nanoscale that must be considered if the material is to be adopted for use by the semiconductor industry.
|
179 |
Strain effect of silicon doped indium nitride films grown by plasma-assisted molecular beam epitaxyYen, Wei-chun 10 August 2010 (has links)
The effect of silicon doping on the strain in c-plane InN films grown on c-plane GaN by plasma-assisted molecular beam epitaxy is investigated. Strain is measured by x-ray reciprocal space mapping and Raman spectroscopy. The silicon doping concentration of our sample is about 1018 cm-3 by Hall measurement. Relation between the strain and the silicon concentration is obtained. To understand the increase in tensile stress caused by Si doping is discussed in terms of a crystallite coalescence model.
|
180 |
Characterization of GaN grown on tilt-cut £^-LiAlO 2 by molecular beam epitaxy for different growth temperaturesLin, Yu-Chiao 19 July 2011 (has links)
We study the properties of m-plane GaN structure on LiAlO 2 substrate grown by
plasma-assisted molecular-beam epitaxy (PAMBE). Lattice parameters of LiAlO 2 are
close to GaN, the interface between LiAlO 2 and GaN showed a good lattice matching.
Low lattice mismatch can reduce the defect generation, improve crystal quality.
However, lattice mismatch still exist, more or less density of defect still can be
observed. The density of defect was reduced in the sample at high temperature.
In this study, we investigate GaN on LiAlO 2 by scanning electron microscope
(SEM), atomic force microscope (AFM), photoluminescence (PL) and X-ray
diffraction (XRD) for different growth temperatures.
|
Page generated in 0.0237 seconds