Papers by Keyword: Heterojunction

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Authors: Hui Liang Zhang, Chun Yuan Zhang, Ding Ding Shi
Abstract: Three different fabrication methods of graphene nanoribbons are discussed. Graphene nanoribbons can be produced through unzipping the carbon nanotubes and also cutting graphene sheets, but with rough edges. Another method is a simple, surface-based bottom-up chemical method without the need for cutting, resulting in high-quality graphene ribbons. The band gap of a graphene ribbon strongly depends on its geometry, particularly its width. The third method creates easily graphene ribbons with different width.
Authors: Laurentiu Fara, Viorel Bădescu
Abstract: The paper discussed the solar cells based on Cu-CdS contact assimilated to a heterojunction. Two methods were considered for our analysis: the rate equations approach and the stochastic equation one. The both permitted to obtain interesting information concerning the specific contact and are characterized by the order parameter.
Authors: R. De Rosa, Maria Luisa Grilli, G. Sasikala, M. Tucci, F. Roca
Authors: Feng Cai, Bo Wu, Yu Feng, Ying Chen, Hong Kuan Yuan, Hong Chen
Abstract: We investigated the atomic rich and defect effects on the half-metallicity of the full-Heusler alloy Co2MnGe from the first principles. Our results show that both Mn-rich and Co-rich could increase the tunnel magnetoresistance (TMR) of the Co2MnGe/MgO magnetic tunnel junctions (MTJs). As for defect, all of investigated Co, Mn and Ge defect show that the spin polarization at Ef and the TMR in the MTJs with Co and Mn defect is significatively decreased except for Ge-defected MTJs.
Authors: A. Franciosi, L. Vanzetti, L. Sorba, A. Bonanni, R. Cingolani, M. Lomascolo, D. Greco
Authors: Peter M. Gammon, Amador Pérez-Tomás, Michael R. Jennings, Ana M. Sanchez, Craig A. Fisher, Stephen M. Thomas, Benedict T. Donnellan, Philip A. Mawby
Abstract: This paper describes the physical and electrical properties of a p-n Si/on-axis SiC vertical heterojunction rectifier. A thin 400nm p-type silicon layer was wafer-bonded to a commercial on-axis SiC substrate by room temperature hydrophilic wafer bonding. Transmission electron microscopy was used to identify the crystallographic orientation as (0001)SiC//(001)Si and to reveal an amorphous interfacial layer. Electrical tests performed on the p-n heterodiodes revealed that, after an additional 1000oC anneal, the rectifier exhibit remarkably low leakage current (10nA/cm2 at an anode voltage of V=-6V), improved on-resistance due to bipolar injection and a turn-on voltage close to the p-n heterojunction theoretical value of 2.4V.
Authors: T.W. MacElwee, J.A. Bardwell, H. Tang, J.B. Webb
Authors: Nathaporn Promros, Kenji Hanada, Motoki Takahara, Takanori Hanada, Ryuji Baba, Phongsaphak Sittimart, Li Chen, Tsuyoshi Yoshitake
Abstract: We prepared n-type nanocrystalline iron disilicide (NC-FeSi2)/intrinsic (i) ultrananocrystalline diamond/amorphous carbon composite (UNCD/a-C)/p-type Si heterojunctions and evaluated as photodiodes. UNCD/a-C and NC-FeSi2 films were deposited by coaxial arc plasma deposition and pulsed laser deposition, respectively. The capacitance-voltage and current-voltage characteristics of heterojunctions were measured at room temperature. The inserted i-UNCD/a-C layer to form pin heterojunctions reduced the capacitance and dark current as compared with those in the case of pn heterojunctions. The build-in potential of heterojunctions was estimated to be 1.2 eV. The prepared heterojunctions showed typical rectifying action and a response for an illumination with a 6 mW, 1.31 μm laser. The recombination process is the predominant mechanism of current transport in the heterojunctions. The dynamic resistance area product and detectivity were 1.54 × 103 Ω cm2 and 5.0 × 108 cmHz1/2/W at-1 V. The evident improvement in the device performance was demonstrated, which should be due to the reduction of dark current by i-UNCD/a-C layer.
Authors: Nathaporn Promros, Ryūhei Iwasaki, Suguru Funasaki, Kyohei Yamashita, Tsuyoshi Yoshitake
Abstract: In order to reduce the parasitic capacitance, mesa structural n-type NC-FeSi2/p-type Si heterojunctions were fabricated by photolithography. Their current-voltage characteristics were measured in the dark and under illumination using a 1.31 μm laser in the temperature range of 60 300 K. Their junction capacitance density was evidently reduced as compared with that of the normal structural diodes. The dark current was markedly reduced with a decrease in the temperature. At 60 K, a rectifying current ratio in the dark became more than five orders of magnitude at ±1V. The ratio of the photocurrent to the dark current was dramatically enhanced to be approximately two orders of magnitude, and the detectivity was calculated to be 1.5 × 1011 cmHz1/2/W at-1V. The obtained results showed a remarkable improvement in the device performance as compared with those at 300 K.
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