Browsing by Author "Ozcelik, S."
Now showing items 1-20 of 27
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Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures
(2010)The optical transitions in AlGaN/GaN heterostructures that are grown by metalorganic chemical vapor deposition (MOCVD) have been investigated in detail by using Hall and room temperature (RT) photoluminescence (PL) ... -
Buffer optimization for crack-free GaN epitaxial layers grown on Si(111) substrate by MOCVD
(Institute of Physics Publishing Ltd., 2008)We report the growth of GaN films on the Si(1 1 1) substrate by metalorganic chemical vapour phase deposition (MOCVD). Different buffer layers were used to investigate their effects on the structural and optical properties ... -
Contributions of impurity band and electron-electron interactions to magnetoconductance in AlGaN
(Taylor & Francis, 2010-06-30)Low temperature electrical measurements of conductivity, the Hall effect and magnetoconductance were performed on a degenerate AlGaN sample. The sample exhibited negative magnetoconductance at low magnetic fields and low ... -
Double subband occupation of the two-dimensional electron gas in InxAl1-XN/AlN/GaN/AlN heterostructures with a low indium content (0.064 ≤ x ≤ 0.140) barrier
(Elsevier, 2010-05-08)We present a carrier transport study on low indium content (0.064 ≤ x ≤ 0.140) InxAl1 - xN/AlN/GaN/AlN heterostructures. Experimental Hall data were carried out as a function of temperature (33-300 K) and a magnetic field ... -
DX-center energy calculation with quantitative mobility spectrum analysis in n-AlGaAs/GaAs structures with low Al content
(ELSEVIER, 2009-03-17)Experimental Hall data that were carried out as a function of temperature (60-350 K) and magnetic field (0-1.4 T) were presented for Si-doped low Al content (x=0.14) n-AlxGa1-xAs/GaAs heterostructures that were grown by ... -
The effect of Si(x)N(y) interlayer on the quality of GaN epitaxial layers grown on Si(111) substrates by MOCVD
(ELSEVIER, 2008-04-27)In the present paper, the effects of nitridation on the quality of GaN epitaxial films grown on Si(111) substrates by metal-organic chemical vapor phase deposition (MOCVD) are discussed. A series of GaN layers were grown ... -
Effects of thermal annealing on the morphology of the AlxGa(1x)N films
(Elsevier, 2010-01-08)Effects of thermal annealing on the morphology of the AlxGa(1-x)N films with two different high Al-contents (x=0.43 and 0.52) have been investigated by atomic force microscopy (AFM). The annealing treatments were performed ... -
Electrical conduction properties of Si δ-doped GaAs grown by MBE
(2009)The temperature dependent Hall effect and resistivity measurements of Si δ-doped GaAs are performed in a temperature range of 25-300 K. The temperature dependence of carrier concentration shows a characteristic minimum at ... -
Electron transport properties in Al0.25Ga0.75N/AlN/GaN heterostructures with different InGaN back barrier layers and GaN channel thicknesses grown by MOCVD
(Wiley, 2012-01-24)The electron transport properties in Al0.25Ga0.75N/AlN/GaN/InxGa1-xN/GaN double heterostructures with various indium compositions and GaN channel thicknesses were investigated. Samples were grown on c-plane sapphire ... -
Electronic transport characterization of AlGaN∕GaN heterostructures using quantitative mobility spectrum analysis
(AIP Publishing LLC, 2007-09-06)Resistivity and Hall effect measurements in nominally undoped Al0.25Ga0.75N/GaN heterostructures grown on sapphire substrate by metal-organic chemical vapor deposition are carried out as a function of temperature (20-350 ... -
Evolution of the mosaic structure in InGaN layer grown on a thick GaN template and sapphire substrate
(Springer, 2013-08-08)The InxGa1-xN epitaxial layers, with indium (x) concentration changes between 0.16 and 1.00 (InN), were grown on GaN template/(0001) Al2O3 substrate by metal organic chemical vapour deposition. The indium content (x), ... -
Grain boundary related electrical transport in Al-rich AlxGa1-xN layers grown by metal-organic chemical vapor deposition
(M A I K Nauka - Interperiodica, 2011)Electrical transport data for Al-rich AlGaN layers grown by metal-organic chemical vapor deposition (MOCVD) are presented and analyzed in the temperature range 135-300 K. The temperature dependence of electrical conductivity ... -
Growth parameter investigation of Al0.25Ga0.75N/GaN/AlN heterostructures with Hall effect measurements
(Institute of Physics Publishing Ltd., 2008-08-08)Hall effect measurements on unintentionally doped Al0.25Ga0.75N/GaN/AlN heterostructures grown by metal organic chemical vapor deposition (MOCVD) were carried out as a function of temperature (20–300 K) and magnetic field ... -
Improvement of breakdown characteristics in AlGaN/GaN/AlxGa 1-xN HEMT based on a grading Al xGa 1-xN buffer layer
(Wiley, 2010-08-03)To improve the breakdown characteristics of an AlGaN/GaN based high electron mobility transistor (HEMT) for high voltage applications, AlGaN/GaN/Al xGa 1-xN double heterostructure (DH-HEMTs) were designed and fabricated ... -
The influence of nitridation time on the structural properties of GaN grown on Si (111) substrate
(Springer, 2009)In the present paper, the effect of in-situ substrate nitridation time on crystalline quality of GaN films grown on Si (111) substrates by metal organic chemical vapor deposition (MOCVD) were investigated. A thin buffer ... -
The influence of thickness and ammonia flow rate on the properties of AIN layers
(Elsevier, 2012)Undoped AlN layers have been grown on c-plane sapphire substrates by metal-organic chemical vapor deposition in order to study the effects of ammonia (NH3) flow rate and layer thickness on the structural quality and surface ... -
Investigation of AlInN HEMT structures with different AlGaN buffer layers grown on sapphire substrates by MOCVD
(ELSEVIER, 2012-06-01)We investigate the structural and electrical properties of Al xIn 1-xN/AlN/GaN heterostructures with AlGaN buffers grown by MOCVD, which can be used as an alternative to AlInN HEMT structures with GaN buffer. The effects ... -
Investigation of low-temperature electrical conduction mechanisms in highly resistive GaN bulk layers extracted with Simple Parallel Conduction Extraction Method
(Springer, 2009-12-03)The electrical conduction mechanisms in various highly resistive GaN layers of Al x Ga1-x N/AlN/GaN/AlN heterostructures are investigated in a temperature range between T=40 K and 185 K. Temperature-dependent conductivities ... -
Large zero-field spin splitting in AlGaN/AlN/GaN/AlN heterostructures
(AIP Publishing LLC, 2009)This work describes Shubnikov-de Haas (SdH) measurements in Al0.22 Ga0.78 N/AlN/GaN/AlN heterostructures. Our experiments coupled with the analysis of the Hall data at various temperatures confirm the formation of a ... -
Numerical optimization of In-mole fractions and layer thicknesses in AlxGa1-xN/AlN/GaN high electron mobility transistors with InGaN back barriers
(ELSEVIER, 2011-02-01)The effects of the In-mole fraction (x) of an InxGa 1-xN back barrier layer and the thicknesses of different layers in pseudomorphic AlyGa1-yN/AlN/GaN/InxGa 1-xN/GaN heterostructures on band structures and carrier densities ...
