Browsing by Subject "Electric conductors"

Now showing 1 - 4 of 4

Open Access
1.3 μm GaAs based resonant cavity enhanced Schottky barrier internal photoemission photodetector
(IEEE, Piscataway, NJ, United States, 2000) Necmi, B.; Kimukin, I.; Özbay, Ekmel; Tuttle, G.
GaAs based photodetectors operating at 1.3 μm that depend on internal photoemission as the absorption mechanism were fabricated. Quantum efficiency (QE) was increased using resonant cavity enhancement (RCE) effect.
Open Access
Atomic strings of group IV, III-V, and II-VI elements
(American Institute of Physics, 2004) Tongay, S.; Durgun, Engin; Çıracı, Salim
A systematic first-principles study of atomic strings made by group IV, III-V, and II-VI elements has revealed interesting mechanical, electronic, and transport properties. The double bond structure underlies their unusual properties. We found that linear chain of C, Si, Ge, SiGe, GaAs, InSb, and CdTe are stable and good conductor, although their parent diamond (zincblende) crystals are covalent (polar) semiconductors but, compounds SiC, BN, AlP, and ZnSe are semiconductors. First row elements do not form zigzag structures.
Open Access
Experimental results for 2D magnetic resonance electrical impedance tomography (MR-EIT) using magnetic flux density in one direction
(Institute of Physics Publishing, 2003) Birgül, Ö.; Eyüboğlu, B. M.; İder, Y. Z.
Magnetic resonance electrical impedance tomography (MR-EIT) is an emerging imaging technique that reconstructs conductivity images using magnetic flux density measurements acquired employing MRI together with conventional EIT measurements. In this study, experimental MR-EIT images from phantoms with conducting and insulator objects are presented. The technique is implemented using the 0.15 T Middle East Technical University MRI system. The dc current method used in magnetic resonance current density imaging is adopted. A reconstruction algorithm based on the sensitivity matrix relation between conductivity and only one component of magnetic flux distribution is used. Therefore, the requirement for object rotation is eliminated. Once the relative conductivity distribution is found, it is scaled using the peripheral voltage measurements to obtain the absolute conductivity distribution. Images of several insulator and conductor objects in saline filled phantoms are reconstructed. The L2 norm of relative error in conductivity values is found to be 13%, 17% and 14% for three different conductivity distributions.
Open Access
Theoretical analysis of poly(difluoroacetylene) PDFA
(Elsevier, 2003) Salzner, U.
Due to the π-donating ability of fluorine, fluorosubstitution has a remarkable effect on the band structure of polyacetylene (PA). Valence and conduction band edges decrease in energy, leading to narrower valence and wider conduction bands. Ionization potential and electron affinity of PDFA are predicted to be about 1.5 eV higher than those of PA. This indicates that PDFA is an excellent candidate for an n-type conductor. PDFA tends to adopt non-planar structures but the energy of planarization is only 5.44 kcal/mol. Alternating difluoroethylene and ethylene units yield planar polymers with decreased band gaps. Ionization potential and electron affinity of the mixed polymer are between those of the homopolymers. © 2003 Elsevier Science B.V. All rights reserved.