| 1. |
- Jain, Vishal, et al.
(författare)
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Study of photocurrent generation in InP nanowire-based p(+)-i-n(+) photodetectors
- 2014
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Ingår i: Nano Reseach. - Beijing & Berlin/Heidelberg : Springer Science and Business Media LLC. - 1998-0124 .- 1998-0000. ; 7:4, s. 544-552
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Tidskriftsartikel (refereegranskat)abstract
- We report on electrical and optical properties of p(+)-i-n(+)photodetectors/solar cells based on square millimeter arrays of InP nanowires (NWs) grown on InP substrates. The study includes a sample series where the p(+)-segment length was varied between 0 and 250 nm, as well as solar cells with 9.3% efficiency with similar design. The electrical data for all devices display clear rectifying behavior with an ideality factor between 1.8 and 2.5 at 300 K. From spectrally resolved photocurrent measurements, we conclude that the photocurrent generation process depends strongly on the p(+)-segment length. Without a p(+)-segment, photogenerated carriers funneled from the substrate into the NWs contribute strongly to the photocurrent. Adding a p(+)-segment decouples the substrate and shifts the depletion region, and collection of photogenerated carriers, to the NWs, in agreement with theoretical modeling. In optimized solar cells, clear spectral signatures of interband transitions in the zinc blende and wurtzite InP layers of the mixed-phase i-segments are observed. Complementary electroluminescence, transmission electron microscopy (TEM), as well as measurements of the dependence of the photocurrent on angle of incidence and polarization, support our interpretations.
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| 2. |
- Suyatin, Dmitry, et al.
(författare)
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Nano-Schottky contacts realized by bottom-up technique
- 2010
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Ingår i: INEC 2010 - 2010 3rd International Nanoelectronics Conference, Proceedings. - Piscataway, N.J. : IEEE Press. - 9781424435432 ; , s. 252-253
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Konferensbidrag (refereegranskat)abstract
- Properties of nanostructures realized by bottom-up techniques are often different from their bulk counterparts. Here we present a study of a nano-Schottky contact formed at the interface between a gold catalytic particle and an epitaxially grown GaxIn1-xAs/InAs nanowire. Selective electrical connections formed to the catalytic particle on one side and to the InAs segment on the other side allowed electrical and optical characterization of the formed junction. We demonstrate that the heterostructure region adjacent to the catalytic particle may act as an ultra-small volume unipolar photodetector with potentially ultra-fast response.
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| 3. |
- Suyatin, Dmitry, et al.
(författare)
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Strong Schottky barrier reduction at Au-catalyst/GaAs-nanowire interfaces by electric dipole formation and Fermi-level unpinning
- 2014
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Ingår i: Nature Communications. - London : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Nanoscale contacts between metals and semiconductors are critical for further downscaling of electronic and optoelectronic devices. However, realizing nanocontacts poses significant challenges since conventional approaches to achieve ohmic contacts through Schottky barrier suppression are often inadequate. Here we report the realization and characterization of low n-type Schottky barriers (~0.35 eV) formed at epitaxial contacts between Au-In alloy catalytic particles and GaAs-nanowires. In comparison to previous studies, our detailed characterization, employing selective electrical contacts defined by high-precision electron beam lithography, reveals the barrier to occur directly and solely at the abrupt interface between the catalyst and nanowire. We attribute this lowest-to-date-reported Schottky barrier to a reduced density of pinning states (~1017 m−2) and the formation of an electric dipole layer at the epitaxial contacts. The insight into the physical mechanisms behind the observed low-energy Schottky barrier may guide future efforts to engineer abrupt nanoscale electrical contacts with tailored electrical properties.
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