| 1. |
- Hussain, I, et al.
(författare)
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Interface trap characterization and electrical properties of Au-ZnO nanorod Schottky diodes by conductance and capacitance methods
- 2012
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 112:6, s. 064506-
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Tidskriftsartikel (refereegranskat)abstract
- Schottky diodes with Au/ZnO nanorod (NR)/n-SiC configurations have been fabricated and their interface traps and electrical properties have been investigated by current-voltage (I-V), capacitance-voltage (C-V), capacitance-frequency (C-f), and conductance-frequency (G(p)/omega-omega) measurements. Detailed and systematic analysis of the frequency-dependent capacitance and conductance measurements was performed to extract the information about the interface trap states. The discrepancy between the high barrier height values obtained from the I-V and the C-V measurements was also analyzed. The higher capacitance at low frequencies was attributed to excess capacitance as a result of interface states in equilibrium in the ZnO that can follow the alternating current signal. The energy of the interface states (E-ss) with respect to the valence band at the ZnO NR surface was also calculated. The densities of interface states obtained from the conductance and capacitance methods agreed well with each other and this confirm that the observed capacitance and conductance are caused by the same physical processes, i.e., recombination-generation in the interface states. (C) 2012 American Institute of Physics.
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| 2. |
- Soomro, Muhammad Yousuf, et al.
(författare)
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Enhancement of zinc interstitials in ZnO nanotubes grown on glass substrate by the hydrothermal method
- 2012
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Ingår i: Applied Physics A. - : Springer Verlag (Germany). - 0947-8396 .- 1432-0630. ; 106:1, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- In this study, high density well aligned ZnO nanotubes were grown on glass via a two-step growth-then-etching by simple and template-free hydrothermal method. We used etching procedure to introduce additional zinc interstitial defects in the ZnO nanotubes. The optical properties of the ZnO nanotubes have been investigated by depth-resolved cathodluminescence spectroscopy (DRCLS) which provides information about the physical origin and growth dependence of optically active defects together with their spatial distribution. The DRCLS study gives clear evidence about the enhancement of zinc interstitial defects which are responsible for the violet and decrease of the DL emission in ZnO nanotubes when compared to the as grown ZnO nanorods. We observed a variation in the zinc interstitials along the nanotube depth.
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| 3. |
- Soomro, Muhammad Yousuf, et al.
(författare)
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Nanoscale elastic modulus of single horizontal ZnO nanorod using nanoindentation experiment
- 2012
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Ingår i: Nanoscale Research Letters. - : Springer. - 1931-7573 .- 1556-276X. ; 7, s. 146-148
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Tidskriftsartikel (refereegranskat)abstract
- We measure the elastic modulus of a single horizontal ZnO nanorod [NR] grown by a low-temperature hydrothermal chemical process on silicon substrates by performing room-temperature, direct load-controlled nanoindentation measurements. The configuration of the experiment for the single ZnO NR was achieved using a focused ion beam/scanning electron microscope dual-beam instrument. The single ZnO NR was positioned horizontally over a hole on a silicon wafer using a nanomanipulator, and both ends were bonded with platinum, defining a three-point bending configuration. The elastic modulus of the ZnO NR, extracted from the unloading curve using the well-known Oliver-Pharr method, resulted in a value of approximately 800 GPa. Also, we discuss the NR creep mechanism observed under indentation. The mechanical behavior reported in this paper will be a useful reference for the design and applications of future nanodevices.
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| 4. |
- Soomro, Muhammad Yousuf, et al.
(författare)
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Piezoelectric power generation from zinc oxide nanowires grown on paper substrate
- 2012
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Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlag Berlin. - 1862-6254 .- 1862-6270. ; 6:2, s. 80-82
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we demonstrate piezoelectric power generation from zinc oxide (ZnO) nanowires grown on paper substrate. Vertically aligned ZnO nanowires are deflected by an atomic force microscopy (AFM) tip in contact mode which generates an output voltage of up to 7 mV. Furthermore, the effects of different parameters mainly influencing the magnitude of the output voltage are discussed. We expect that due to its simplicity, this approach represents an important step within the development of nanoscale power generators. It offers a promising alternative powering source for the next generation of nanodevices on disposable paper.
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