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Metalorganic Chemical Vapour Deposition (metalorganic + chemical_vapour_deposition)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Low-cost growth of AlN using vectored-flow epitaxy for the purpose of water sterilisation in a rural environment

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2008
Matthew Branch
Abstract The high V/III ratio required for the Metalorganic Chemical Vapour Deposition (MOCVD) growth of AlN using the precursors trimethylaluminium and ammonia have contributed to the excessive costs of producing ultra violet light emitting diodes (UVLEDs) which can be used in water purification. This paper introduces a novel growth technique, vectored-flow epitaxy (VFE), which maintains the separation between gaseous reagents within the growth chamber. In addition, the VFE technique, which employs atmospheric pressure growth, also pre cracks the ammonia prior to injection and thereby significantly reduces the high V/III ratio required for the growth of this material. The pre cracked ammonia also removes the need for high growth temperatures, which is known to be necessary for its thermal decomposition. With this technique, 2 ,m/h growth is possible at a V/III ratio of 50. These advances will contribute to the development of a cost-effective solution to the treatment of drinking water in a rural environment. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Mg-doped AlGaN grown on an AlN/sapphire template by metalorganic chemical vapour deposition

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2006
Hongbo Yu
Abstract The growth of high-performance Mg-doped p-type AlxGa1,xN (x = 0.35) layers using low-pressure metalorganic chemical vapour deposition on an AlN/sapphire template is reported. The influence of growth conditions on the p-type conductivity of the AlxGa1,xN (x = 0.35) alloy was investigated. It was found that the p-type resistivity of the AlGaN alloy demonstrates a marked dependence on the Mg concentration, V/III ratio and group III element flow rate. A minimum p-type resistivity of 3.5 , cm for AlxGa1,xN (x = 0.35) epilayers was achieved. A Ni/Au (10 nm/100 nm) ohmic contact was also fabricated and a specific contact resistivity of 8.1 × 10,2 , cm2 was measured. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

GaN-based deep green light emitting diodes on silicon-on-insulator substrates

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009
S. Tripathy
Abstract We have demonstrated deep green InGaN/GaN light emitting diodes (LEDs) on 100 nm thick (111)-oriented silicon-on-insulator (SOI) substrate. The LED structures are grown by metalorganic chemical vapour deposition. High-resolution X-ray diffraction and transmission electron microscopy have been used to characterize the structural quality of the LED layers. The room temperature electroluminescence (EL) spectrum from these LEDs is dominated by multiple interference peaks associated with the reflectivity changes at the bottom Si/SiO2 interfaces beneath AlN buffer. The spectral intensity of the LEDs in the deep green region is higher due to the larger substrate reflectance at longer wavelengths. A greater modulation in the spectral fringes in the longer wavelength regions is due to the presence of Fabry-Perot modes. Such InGaN/GaN light emitting structures on reflective SOI may be useful for the realization of phosphor-free white LEDs. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

AlGaN films grown on trenched sapphire substrates using a low-temperature GaNP buffer layer by MOCVD

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
K. Sumiyoshi
Abstract A technique has been developed to grow low-dislocation-density AlGaN films in this paper. The AlGaN film is laterally overgrown on a trenched sapphire substrate with a low-temperature (LT) GaNP buffer layer by metalorganic chemical vapour deposition (MOCVD). The optical charactertics and microstructure of the AlGaN films have been invesigated by means of cathodoluminescence (CL), high-resolution X-ray diffraction (HRXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. It is shown that the dislocation densities in the Al0.07Ga0.93N film are reduced to 8.7 x 108 cm,2 (by CL) and 2.7 x 109 cm,2 (by TEM) in the whole trenched sapphire, and 4.0 x 108 cm,2 (by CL) and 1.3 x 109 cm,2 (by TEM) in the trenched area. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]