Browsing by Author "Kasap, M."
Now showing items 1-20 of 24
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Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures
Bengi, A.; Lisesivdin, S.B.; Kasap, M.; Mammadov, T.; Ozcelik, S.; Özbay, Ekmel (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) ... -
Comparison of the transport properties of high quality AlGaN/AlN/GaN and AllnN/AlN/GaN two-dimensional electron gas heterostructures
Tülek, R.; Ilgaz, A.; Gökden, S.; Teke, A.; Öztürk, M. K.; Kasap, M.; Özçelik, S.; Arslan, E.; Özbay, Ekmel (AIP Publishing LLC, 2009-01-07)The transport properties of high mobility AlGaN/AlN/GaN and high sheet electron density AlInN/AlN/GaN two-dimensional electron gas (2DEG) heterostructures were studied. The samples were grown by metal-organic chemical vapor ... -
Contributions of impurity band and electron-electron interactions to magnetoconductance in AlGaN
Tasli, P.; Yildiz, A.; Kasap, M.; Özbay, Ekmel; Lisesivdin, S. B.; Ozcelik, S. (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 ... -
Determination of the critical indium composition corresponding to the metal-insulator transition in InxGa1-xN (0.06 ≤ x ≤ 0.135) layers
Yildiz, A.; Lisesivdin, S. B.; Tasli, P.; Özbay, Ekmel; Kasap, M. (Elsevier, 2009-10-13)The low-temperature conductivity of InxGa1-xN alloys (0.06 ≤ x ≤ 0.135) is analyzed as a function of indium composition (x). Although our InxGa1-xN alloys were on the metallic side of the metal-insulator transition, neither ... -
Determination of two-dimensional electron and hole gas carriers in AlGaN/GaN/AlN heterostructures grown by Metal Organic Chemical Vapor Deposition
Acar, S.; Lisesivdin, S. B.; Kasap, M.; Özcelik, S.; Özbay, Ekmel (Elsevier BV, 2008-02-29)Resistivity and Hall effect measurements on nominally undoped Al0.25Ga0.75N/GaN/AlN heterostructures grown on sapphire substrates prepared by metal organic chemical vapor deposition have been carried out as a function of ... -
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
Lisesivdin, S. B.; Tasli, P.; Kasap, M.; Ozturk, M.; Arslan, E.; Ozcelik, S.; Özbay, Ekmel (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
Lisesivdin, S. B.; Altuntas, H.; Yildiz, A.; Kasap, M.; Özbay, Ekmel; Ozcelik, S. (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 strain relaxation on electron transport in undoped Al0.25Ga0.75N/GaN heterostructures
Lişesivdin, S. B.; Yıldız, A.; Acar, S.; Kasap, M.; Özçelik, S.; Özbay, Ekmel (Elsevier BV * North-Holland, 2007-11-01)The two-dimensional electron gas (2DEG) transport properties of two-step growth undoped Al0.25Ga0.75N/GaN heterostructures with semi-insulating buffer, grown by MOCVD, were investigated in a temperature range of 20–350 ... -
Electrical conduction properties of Si δ-doped GaAs grown by MBE
Yildiz, A.; Lisesivdin, S.B.; Altuntas H.; Kasap, M.; Ozcelik, S. (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
Kelekci, O.; Tasli, P. T.; Yu, H.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (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
Lisesivdin, S. B.; Yildiz, A.; Acar, S.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (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 ... -
Grain boundary related electrical transport in Al-rich AlxGa1-xN layers grown by metal-organic chemical vapor deposition
Yildiz, A.; Tasli, P.; Sarikavak, B.; Lisesivdin, S. B.; Ozturk, M. K.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (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
Lisesivdin, S. B.; Demirezen, S.; Caliskan, M. D.; Yildiz, A.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (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 ... -
Investigation of AlInN HEMT structures with different AlGaN buffer layers grown on sapphire substrates by MOCVD
Kelekci, O.; Tasli, P.; Cetin, S. S.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (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
Yildiz, A.; Lisesivdin, S. B.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel; Balkan, N. (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
Lisesivdin, S. B.; Balkan, N.; Makarovsky, O.; Patanè, A.; Yildiz, A.; Caliskan, M. D.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (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 Al-mole fractions and layer thicknesses in normally-on AlGaN-GaN double-channel high electron mobility transistors (DCHEMTs)
Atmaca, G.; Elibol, K.; Lisesivdin, S. B.; Kasap, M.; Özbay, Ekmel (Institutul National de Cercetare-Dezvoltare pentru Optoelectronica, 2009-05)We explored the effects of the Al-mole fraction (x) of AlxGa1-xN barrier layers and the thickness of some layers on carrier densities and electron probability densities in normally-on AlGaN-GaN double-channel high electron ... -
The persistent photoconductivity effect in AIGaN/GaN heterostructures grown on sapphire and SiC substrates
Arslan, E.; Butun, S.; Lisesivdin, S. B.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (AIP Publishing LLC, 2008)In the present study, we reported the results of the investigation of electrical and optical measurements in Al(x)Ga(1-x)N/GaN heterostructures (x=0.20) that were grown by way of metal-organic chemical vapor deposition on ... -
Scattering analysis of 2DEG carrier extracted by QMSA in undoped Al0.25Ga0.75N/GaN heterostructures
Lisesivdin, S. B.; Acar, S.; Kasap, M.; Ozcelik, S.; Gokden, S.; Özbay, Ekmel (Institute of Physics Publishing Ltd., 2007)Hall effect measurements on undoped Al0.25Ga0.75N/GaN heterostructures grown by a metalorganic chemical vapour deposition (MOCVD) technique have been carried out as a function of temperature (20-350 K) and magnetic field ... -
Scattering analysis of two-dimensional electrons in AlGaN/GaN with bulk related parameters extracted by simple parallel conduction extraction method
Lisesivdin, S. B.; Yildiz, A.; Balkan, N.; Kasap, M.; Ozcelik, S.; Özbay, Ekmel (American Institute of Physics, 2010-07-15)We carried out the temperature (22-350 K) and magnetic field (0.05 and 1.4 T) dependent Hall mobility and carrier density measurements on Al 0.22Ga0.78N/GaN heterostructures with AlN interlayer grown by metal-organic ...