« Previous
1
Next »
(9 hits, 1/1)
Showing
10, 25, 50, 100, 500, 1000, all papers per page.
Sort by:
last publication date,
older publication date,
last update date.
- 1. J.Am.Chem.Soc. 130, 48 (2008) , ACS , “Enhanced Ferromagnetism and Tunable Saturation Magnetization of Mn/C Codoped GaN Nanostructures Synthesized by Carbothermal Nitridation”, Zeyan Wang, Baibiao Huang, Lin Yu, Ying Dai, Peng Wang, Xiaoyan Qin, Xiaoyang Zhang, Jiyong Wei, Jie Zhan, Xiangyang Jing, Haixia Liu, and Myung-Hwan WhangboMn/C-codoped GaN nanostructures were synthesized by carbothermal nitridation with active charcoal as the carbon source. Nanostructures such as zigzag nanowires and nanoscrews were observed by varying the reaction time and the C/Ga molar ratio of the starting material used for the synthesis. The structures and morphologies of the as-grown samples were characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy measurements. The doping of both Mn and C in the GaN matrix was confirmed by X-ray photoelectron spectroscopy measurements, and the ferromagnetic properties of Mn/C-codoped GaN samples were confirmed by room-temperature magnetization measurements. The saturation magnetization of Mn/C-codoped GaN increases steadily with increasing C/Ga molar ratio of the starting material at a rate of ~0.023 emu/g per C/Ga molar ratio, and the ferromagnetism of Mn/C-codoped GaN can be stronger than that of Mn-doped GaN by a factor of ~40. A plausible growth mechanism was proposed, and the role of carbon codoping in tuning the morphology and ferromagnetic property was discussed. Our work suggests that carbon doping in the GaN matrix favors the N sites over the Ga sites, Mn/C-codoping in the GaN matrix is energetically favorable, and the C-codoping strongly enhances the preference of the FM coupling to the AFM coupling between the two doped Mn sites. These suggestions were probed on the basis of first-principles density functional theory electronic structure calculations for a number of model doped structures constructed with a 32-atom 2 × 2 × 2 supercell. (Read more)
- 2. Phys. Rev. Lett. 98, 206406 (2007) , “Role of Intermolecular Coupling in the Photophysics of Disordered Organic Semiconductors: Aggregate Emission in Regioregular Polythiophene”, Jenny Clark, Carlos Silva, Richard H. Friend, and Frank C. SpanoWe address the role of excitonic coupling on the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical emission is overwhelmingly dominated by weakly coupled H... (Read more)
- 3. J. Appl. Phys. 100, 043706 (2006) , “Electrical properties of unintentionally doped semi-insulating and conducting 6H-SiC”, W. C. Mitchel, W. D. Mitchell, Z. Q. Fang, D. C. Look, S. R. Smith, H. E. Smith, Igor Khlebnikov, Y. I. Khlebnikov, C. Basceri, and C. BalkasTemperature dependent Hall effect (TDH), low temperature photoluminescence (LTPL), secondary ion mass spectrometry (SIMS), optical admittance spectroscopy (OAS), and thermally stimulated current (TSC) measurements have been made on 6H-SiC grown by the physical vapor transport technique... (Read more)
- 4. J. Appl. Phys. 99, 123514 (2006) , “Study of the annealing kinetic effect and implantation energy on phosphorus-implanted silicon wafers using spectroscopic ellipsometry”, Emmanouil Lioudakis, Constantinos Christofides, and Andreas OthonosIn this work, we have studied the changes in the optical properties on crystalline silicon implanted wafers (1×10131×1016 P+/cm2) using an extensive ellipsometric analysis. The effects of implantation energy (20180 KeV) and... (Read more)
- 5. J. Appl. Phys. 99, 113520 (2006) , “Effects of hydrogen bond redistribution on photoluminescence of a-SiC:H films under thermal treatment”, A. V. Vasin, S. P. Kolesnik, A. A. Konchits, V. I. Kushnirenko, V. S. Lysenko, A. N. Nazarov, A. V. Rusavsky, and S. AshokHydrogenated amorphous silicon carbide (a-SiC:H) films have been deposited using magnetron sputtering technique. An integrated investigation of the effect of vacuum annealing temperature on photoluminescence properties and paramagnetic defects and its correlation with structural... (Read more)
- 6. Phys. Rev. Lett. 96, 145501 (2006) , “Identification of the Carbon Antisite-Vacancy Pair in 4H-SiC”, T. Umeda, N. T. Son, J. Isoya, E. Janzn, T. Ohshima, N. Morishita, H. Itoh, A. Gali, M. BockstedteThe metastability of vacancies was theoretically predicted for several compound semiconductors alongside their transformation into the antisite-vacancy pair counterpart; however, no experiment to date has unambiguously confirmed the existence of antisite-vacancy pairs. Using electron paramagnetic resonance and first principles calculations we identify the SI5 center as the carbon antisite-vacancy pair in the negative charge state (CSiVC-) in 4H-SiC. We suggest that this defect is a strong carrier-compensating center in n-type or high-purity semi-insulating SiC. (Read more)SiC| ENDOR EPR Theory electron-irradiation optical-spectroscopy thermal-meas./anneal-exp.| -1 -2 1.0eV~ 13C 29Si C1h C3v Carbon Csi EI5/6 HEI1 HEI5/6 Nitrogen P6/7 SI5 Silicon Vc antisite bistable/metastable dangling-bond n-type pair(=2) semi-insulating vacancy .inp files: SiC/SI5_C1h SiC/SI5_80K SiC/SI5_100K | last update: Takashi Fukushima
- 7. Phys. Rev. B 67, 195338 (2003) , “Layer-resolved kinetics of Si oxidation investigated using the reflectance difference oscillation method”, T. Yasuda, N. Kumagai, M. Nishizawa, S. Yamasaki, H. Oheda, and K. YamabeDry oxidation kinetics of the Si(001) surface has been investigated using reflectance difference oscillation to resolve atomic-scale phenomena. The activation energy for oxidation has been found to increase as the oxide-Si interface moves in the depth direction, reaching the value for bulk... (Read more)
- 8. Mater. Sci. Eng. R 33, 135-207 (2001) , “Comprehensive characterization of hydride VPE grown GaN layers and templates”, H. MorkoçGaN community has recently recognized that it is imperative that the extended, and point defects in GaN and related materials, and the mechanisms for their formation are understood. This is a first and an important step, which must be followed by defect reduction before full implementation of this... (Read more)
- 9. Phys. Rev. Lett. 51, 423 (1983) , “Creation of Quasistable Lattice Defects by Electronic Excitation in SiO2”, Katsumi Tanimura, Takeshi Tanaka, and Noriaki ItohThe transient volume change of ?-quartz and fused silica induced by irradiation with an electron pulse has been measured above 80 K. It is shown that transient changes of volume and optical absorption due to the E1? centers (oxygen vacancies) decay in parallel and that the... (Read more)
« Previous
1
Next »
(9 hits, 1/1)
Showing
10, 25, 50, 100, 500, 1000, all papers per page.
Sort by:
last publication date,
older publication date,
last update date.
All papers (3399)
Updated at 2010-07-20 16:50:39
Updated at 2010-07-20 16:50:39
(view as: tree
,
cloud
)
1329 | untagged |
Materials
(111 tags)
Others(101 tags)
Technique
(46 tags)
Details
(591 tags)
Bond(35 tags)
Defect(interstitial)(18 tags)
Defect(vacancy)(15 tags)
Defect-type(19 tags)
Element(65 tags)
Energy(8 tags)
Isotope(56 tags)
Label(303 tags)
Sample(17 tags)
Spin(8 tags)
Symmetry(15 tags)