Papers by Keyword: Al Doping

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Authors: Akihiro Ikeda, Rikuho Sumina, Hiroshi Ikenoue, Tanemasa Asano
Abstract: Al doping of 4H-SiC with high surface concentration and deep depth profile is found to be realized by irradiating single-pulse excimer laser to an Al film deposited on the surface. Optical emission spectra suggest that high-temperature molten Al is produced behind the laser-generated high-density Al plasma and Al is diffused from the molten Al into 4H-SiC. The Al doping depth reaches to ~200 nm by irradiating a single laser pulse. A pn junction diode fabricated by the doping with the molten Al shows on/off ratio over 10 orders of magnitude.
Authors: Chong Mu Lee, Keun Bin Yim, Choong Mo Kim
Abstract: ZnO:Al thin films were deposited on sapphire(001) substrates by RF magnetron sputtering. Effects of the O2/Ar flow ratio in the sputtering process on the crystallinity, surface roughness, carrier concentration, carrier mobility, and optical properties of the films were investigated. AFM analysis results show that the surface roughness is lowest at the O2/Ar flow ratio of 0.5 and tends to increase owing to the increase of the grain size as the O2/Ar flow ratio increases further than 0.5. According to the Hall measurement results the resistivity increases as the O2/Ar flow ratio increases. The transmittance of the film tends to increase as the O2/Ar gas flow ratio increases up to 0.5 but it nearly does not change with continued increases in the O2/Ar flow ratio. Considering the effects of the the O2/Ar flow ratio on the surface roughness, electrical resistivity and transmittance properties of the ZnO:Al film the optimum O2/Ar flow ratio is 0.5 in the RF magnetron sputter deposition of the ZnO:Al film.
Authors: Chao Xu, Shi Min Liu, Wan Yu Ding, Chao Qian Liu, Wei Ping Chai
Abstract: Finely dispersed Al-doped ZnO (AZO) nanoparticles with well crystallization were prepared by a modified sol-gel combustion synthesis. The AZO nanoparticles with different Al doping concentration were calcined at 600 °C. In order to investigate the physical properties and microstructural characteristics, the nanoparticles were characterized by bulk density measurement, scanning electron microscope (SEM) and X-ray diffraction (XRD). The XRD patterns of AZO nanoparticles corresponded well to the hexagonal structure of ZnO, indicating that the partial Zn atoms were substituted by Al atoms. With the increase of Al doping concentration, the size of AZO nanoparticles decreased from 30.43 nm to 25.97 nm. Simultaneously, with changing the atom ratio of Al/Zn, the bulk density varied obviously.
Authors: Shu Ming Yang, Guang Hui Zhu, Shu Pei Guo
Abstract: In this paper, Al(NO3)3•9H2O was used as raw material and the nanoparticles of Al-doped TiO2 were prepared by hydrothermal method. The nanoparticles and films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Ultraviolet and Visible Spectroscopy (UV-Vis). The flat band potential (Efb) of nanostructured TiO2 and Al-doped TiO2 in acetone have been determined with spectroelectrochemistry measurement. The results show that Al doping decreases the energy gap and improves the absorption ability in visible region. On the other hand, Al doping TiO2 can effectively embarrass the crystal growth of TiO2. Specifically, the Efb of TiO2 and Al-doped TiO2 can be determined to be -0.6 V and -0.3V.
Authors: Sylvie Contreras, Leszek Konczewicz, Pawel Kwasnicki, Roxana Arvinte, Hervé Peyre, Thierry Chassagne, Marcin Zielinski, Maria Kayambaki, Sandrine Juillaguet, Konstantinos Zekentes
Abstract: In the range 80 K-900 K, we have investigated the electrical properties of heavily aluminum in-situ doped, 4H-SiC samples. The temperature dependence of the hole concentration and Hall mobility was analyzed in the model taking into account heavy and light holes. The modelisation parameters were compared with experimental values of Secondary Ion Mass Spectroscopy (SIMS) and Capacitance-Voltage (CV) measurements.
Authors: Seon Hye Kim, Kwang Bo Shim, Kyoung Ran Han, Chang Sam Kim
Abstract: Al doped Li(Ni1/3Co1/3Mn1/3-xAlx)O2 (x=0.005, 0.01, 0.05) and Li(Ni1/3-x/2Co1/3Mn1/3-x/2Alx)O2 (x=0.01, 0.05) cathode materials for lithium ion batteries were synthesized using an ultrasonic spray pyrolysis and heat treatment. The substitution with Al reduced the content of Mn3+, promoted grain growth, and broadened the particle size distribution of synthesized powders. The initial discharge capacity of cells made with 0.5 mol% Al doped Li(Ni1/3Co1/3Mn1/3-0.005Al0.005)O2 powder was as high as that of the undoped (~180 mAhg-1, 3.04.5 V), and showed an excellent cycle stability. The improvement of the cycle stability was considered to be due to the decrease of Mn3+ in Li(Co1/3Ni1/3Mn1/3-xAlx)O2 by Al doping.
Authors: Marcin Zielinski, Carole Balloud, Sandrine Juillaguet, Bernard Boyer, Véronique Soulière, Jean Camassel
Abstract: Recently, a systematic comparison of SIMS measurements with LTPL (Low Temperature Photoluminescence) spectra led us to propose a straightforward empirical calibration of the LTPL intensity versus Al content in 4H-SiC samples. In the present work we analyze the effect of the LTPL excitation power on the intensity of the Al-related features. We examine the influence of the excitation conditions on the calibration curve and determine the limitations of the method.
Authors: Christophe Jacquier, Gabriel Ferro, Carole Balloud, Marcin Zielinski, Jean Camassel, Efstathios K. Polychroniadis, J. Stoemenos, François Cauwet, Yves Monteil
Authors: Björn Sundqvist, Alexsandre Ellison, A.K. Jonsson, Anne Henry, Christer Hallin, Peder Bergman, Björn Magnusson, Erik Janzén
Authors: Kazuma Eto, Hiromasa Suo, Tomohisa Kato, Hajime Okumura
Abstract: Low resistivity p-type SiC bulk crystals were grown by the sublimation method with using aluminum and nitrogen co-doping. In the sublimation growth of 4H-SiC, to obtain low-resistive p-type crystals are not easy because of the instability of 4H-SiC polytype with highly Al-doping. We have grown < 90 mΩcm p-type 4H-SiC bulk crystals with the co-doping condition. The results of SIMS and Raman spectroscopy show that high concentration of nitrogen co-doping could be effective to the stabilization of 4H polytype with p-type SiC growth.
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