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An HVPE reactor for the growth of bulk GaN crystals with a diameter of 50 mm was developed. Growth rate non-uniformity of 1% was achieved using an axisymmetric vertical gas injector with stagnation point flow. Chemically-resistant…

Selective area growth of GaN nanostructures has been performed on full 2" c-sapphire substrates using Si3N4 mask patterned by nanoimprint lithography (array of 400 nm diameter circular holes). A new process has been developed to improve the…

Several ten $\mu$m GaN have been deposited on a silicon substrate using a two-step hydride vapor phase epitaxy (HVPE) process. The substrates have been covered by AlN layers and GaN nanostructures grown by plasma-assisted molecular-beam…

Materials Science · Physics 2016-05-25 U. Jahn , M. Musolino , J. Lähnemann , P. Dogan , S. Fernández Garrido , J. F. Wang , K. Xu , D. Cai , L. F. Bian , X. J. Gong , H. Yang

Gallium oxide films were grown by HVPE on (0001) sapphire substrates with and without $\alpha$-Cr$_2$O$_3$ buffer produced by RF magnetron sputtering. Deposition on bare sapphire substrates resulted in a mixture of $\alpha$-Ga$_2$O$_3$ and…

Large area epitaxy of two-dimensional (2D) layered materials with high material quality is a crucial step in realizing novel device applications based on 2D materials. In this work, we report high-quality, crystalline, large-area gallium…

The control over impurities like hydrogen and oxygen is of key importance in nitride-based semiconducting due to their unrivaled applicability in optoelectronics and high power/high frequency electronics. Therefore, it is desirable to…

Materials Science · Physics 2020-08-04 Rafal Jakiela , Adam Barcz

We report on the impact of growth conditions on surface hillock density of N-polar GaN grown on nominally on-axis (0001) sapphire substrate by metal organic chemical vapor deposition (MOCVD). Large reduction in hillock density was achieved…

Materials Science · Physics 2017-05-12 Jonathan Marini , Jeffrey Leathersich , Isra Mahaboob , John Bulmer , Neil Newman , F. , Shahedipour-Sandvik

In this study we report on a novel two-step epitaxial growth technique that enables a significant improvement of the crystal quality of nitrogen-polar GaN. The starting material is grown on 4{\deg} vicinal sapphire substrates by metal…

Materials Science · Physics 2024-08-06 Pietro Pampili , Vitaly Z. Zubialevich , Peter J. Parbrook

In this work, we report on the growth of hexagonal boron nitride (hBN) crystals from an iron flux at atmospheric pressure and high temperature and demonstrate that (i) the entire sheet of hBN crystals can be detached from the metal in a…

High quality semipolar and nonpolar GaN is crucial in achieving high-performance GaN-based optoelectronic devices, yet it has been very challenging to achieve large-area wafers that are free of basal-plane stacking faults (BSFs). In this…

Materials Science · Physics 2018-10-17 Jie Song , Joowon Choi , Cheng Zhang , Zhen Deng , Yujun Xie , Jung Han

In this article, high composition (>35%) thick (>30 nm) barrier AlGaN/AlN/GaN HEMT structure grown on a sapphire substrate with ultra-low sheet resistivity (<250 \Omega / \Box ) is reported. Optimization of growth conditions, such as…

Recently theorized hybrid II-IV-N{_2} / III-N heterostructures, based on current commercialized (In,Ga)N devices, are predicted to significantly advance the design space of highly efficient optoelectronics in the visible spectrum, yet there…

Materials Science · Physics 2020-02-11 M. Brooks Tellekamp , Celeste L. Melamed , Andrew G. Norman , Adele Tamboli

Cracking of thick GaN films on sapphire substrates during the cooling down after the growth was studied. The cracking was suppressed by increasing the film-to-substrate thickness ratio and by using an intermediate carbon buffer layer, that…

Materials Science · Physics 2019-03-06 Vladislav Voronenkov , Andrey Leonidov , Yuri Lelikov , Andrey Zubrilov , Yuri Shreter

Cubic GaN layers were grown by plasma-assisted molecular beam epitaxy on 3C-SiC (001)substrates. In situ reflection high energy electron diffraction was used to quantitatively determine the Ga coverage of the GaN surface during growth.…

Materials Science · Physics 2007-05-23 J. Schoermann , S. Potthast , D. J. As , K. Lischka

GaN films with thickness up to 3 mm were grown by halide vapour phase epitaxy method. Two growth modes were observed: the high temperature (HT) mode and the low temperature (LT) mode. Films grown in HT mode had smooth surface, however the…

In metal organic vapor phase epitaxy of GaN, the growth mode is sensitive to reactor temperature. In this study, V-pit-shaped GaN has been grown on normal c-plane cone-patterned sapphire substrate by decreasing the growth temperature of…

Materials Science · Physics 2016-11-28 Lai Wang , Xiao Meng , Di Yang , Zhibiao Hao , Yi Luo , Changzheng Sun , Yanjun Han , Bing Xiong , Jian Wang , Hongtao Li

The spectrum of two-dimensional (2D) materials beyond graphene offers a remarkable platform to study new phenomena in condensed matter physics. Among these materials, layered hexagonal boron nitride (hBN), with its wide bandgap energy…

We demonstrate the top-down fabrication of ordered arrays of GaN nanowires by selective area sublimation of pre-patterned GaN(0001) layers grown by hydride vapor phase epitaxy on Al$_{2}$O$_{3}$. Arrays with nanowire diameters and spacings…

GaN films with thicknesses up to 3 mm were grown in two custom-made halide vapor phase epitaxy (HVPE) reactors. V-shaped defects (pits) with densities from 1 cm$^{-2}$ to 100 cm$^{-2}$ were found on the surfaces of the films. Origins of pit…

Transparent and colorless hexagonal boron nitride (hBN) single crystals were grown from the Mg-B-N system using high-pressure high-temperature cubic anvil technique. By varying the synthesis conditions we could determine the sequence of…

Materials Science · Physics 2014-07-09 N. D. Zhigadlo
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