Multiple-Trapping Governed Electron Transport and Charge Separation in ZnO/In<sub>2</sub>S<sub>3</sub> Core/Shell Nanorod Heterojunctions

Strothkämper, Christian; Schwarzburg, Klaus; Schütz, Robert; Eichberger, Rainer; Bartelt, Andreas

doi:10.1021/jp2071748

Cited by 36 publications

(34 citation statements)

References 42 publications

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“…23,29,[34][35][36]39,71,73,76 Alternatively, the Drude-Smith model has also been used as an EMT in its own right and fit directly to the measured THz conductivity. [9][10][11][12][13][14][15][16][17][18][19]21,22,[25][26][27]30,31,33,38,[41][42][43][44][45]48 Each approach begins with a different physical process and leads to its own difficulties when one interprets the subsequent fits to the data.…”

Section: −48mentioning

confidence: 99%

Microscopic origin of the Drude-Smith model

et al. 2017

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The Drude-Smith model has been used extensively in fitting the THz conductivities of nanomaterials with carrier confinement on the mesoscopic scale. Here, we show that the conventional 'backscattering' explanation for the suppression of low-frequency conductivities in the Drude-Smith model is not consistent with a confined Drude gas of classical non-interacting electrons and we derive a modified Drude-Smith conductivity formula based on a diffusive restoring current. We perform Monte Carlo simulations of a model system and show that the modified Drude-Smith model reproduces the extracted conductivities without free parameters. This alternate route to the DrudeSmith model provides the popular formula with a more solid physical foundation and well-defined fit parameters.

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Section: −48mentioning

confidence: 99%

Microscopic origin of the Drude-Smith model

et al. 2017

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“…Further details of the experimental setup have been described previously. [64] The THz pulse is generated by optical rectification in a ZnTe crystal. A series of parabolic mirrors guide the THz probe pulse onto the sample and focus the transmitted signal onto the detection sequence based on electro-optic sampling.…”

Section: Time-resolved Spectroscopy: Time-resolved Microwave Conductimentioning

confidence: 99%

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Jang

Friedrich

Müller

et al. 2017

Advanced Energy Materials

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Widespread application of solar water splitting for energy conversion is largely dependent on the progress in developing not only efficient, but also cheap and scalable photoelectrodes. Metal oxides, which can be deposited with scalable techniques and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). In this paper, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one of the most promising metal oxide photoelectrodes, as a method to overcome the carrier transport limitations. Timeresolved microwave and terahertz conductivity measurements reveal more than two-fold enhancement of the carrier lifetime for the hydrogen-treated BiVO4, without significantly affecting the carrier mobility. This is in contrast to the case of tungsten-doped BiVO4, although hydrogen is also shown to be a donor type dopant in BiVO4. The enhancement in carrier lifetime is found to be caused by significant reduction of trap-assisted recombination, either via passivation of deep trap states or reduction of trap state density, which can be related to vanadium anti-site on bismuth or vanadium interstitials according to density functional theory calculations. Overall, these findings provide further insights on the interplay between defect modulation and carrier transport in metal oxide photoelectrodes, which will benefit the development of low-cost, highly-efficient solar energy conversion devices.

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“…The OPTP spectrometer has been described earlier [23]. The setup has been modified recently to record the pump induced change in THz reflection configuration.…”

Section: Film Synthesis and Characterizationmentioning

confidence: 99%

Effects of Disorder on Carrier Transport inCu2SnS3

et al. 2015

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In recent years, further improvements in the efficiency of Cu2ZnSn(S,Se)4 photovoltaic devices have been hampered due to several materials issues, including cation disorder. Cu2SnS3 is a promising new absorber material that has attracted significant interest in recent years. However, similar to CZTS, Cu2SnS3 displays cation disorder. In this work, we develop synthetic techniques to control the disorder in Cu2SnS3 thin films. By manipulating the disorder in this material, we observe crystal structure changes and detect improvements in the majority carrier (hole) transport. However, when the minority carrier (electron) transport was investigated using optical pump terahertz probe spectroscopy, minimal differences were observed between the ordered and disordered Cu2SnS3. By combining these results with first-principles and Monte Carlo theoretical calculations, we are able to conclude that even ostensibly "ordered" Cu2SnS3 displays minority carrier transport properties corresponding to the disordered structure. The presence of extended planar defects in all samples, observed in TEM imaging, suggests that disorder is present even when it is not detectable using traditional structural characterization methods. The results of this study highlight some of the challenges to the further improvement of Cu2SnS3-based photovoltaics, and have implications for other disordered multinary semiconductors such as CZTS.

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Multiple-Trapping Governed Electron Transport and Charge Separation in ZnO/In₂S₃ Core/Shell Nanorod Heterojunctions

Abstract: Sample Preparation. ZnO nanorods were grown on 1.5 mm thick [0001] oriented quartz substrates by chemical bath deposition (0.4 M NaOH and 0.01 M ZnNO 3 ) at 80 °C. A 40 nm thick ZnO seed layer was deposited on the substrates prior to nanorod

Cited by 36 publications

References 42 publications

Microscopic origin of the Drude-Smith model

Microscopic origin of the Drude-Smith model

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Effects of Disorder on Carrier Transport inCu2SnS3

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Multiple-Trapping Governed Electron Transport and Charge Separation in ZnO/In2S3 Core/Shell Nanorod Heterojunctions

Abstract: Sample Preparation. ZnO nanorods were grown on 1.5 mm thick [0001] oriented quartz substrates by chemical bath deposition (0.4 M NaOH and 0.01 M ZnNO 3 ) at 80 °C. A 40 nm thick ZnO seed layer was deposited on the substrates prior to nanorod

Cited by 36 publications

References 42 publications

Microscopic origin of the Drude-Smith model

Microscopic origin of the Drude-Smith model

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Effects of Disorder on Carrier Transport inCu2SnS3

Contact Info

Product

Resources

About

Multiple-Trapping Governed Electron Transport and Charge Separation in ZnO/In₂S₃ Core/Shell Nanorod Heterojunctions