نتایج جستجو برای: photoconductivity

تعداد نتایج: 1006  

2014
Y. C. Jiang J. Gao

Traditionally, strain effect was mainly considered in the materials with periodic lattice structure, and was thought to be very weak in amorphous semiconductors. Here, we investigate the effects of strain in films of cobalt-doped amorphous carbon (Co-C) grown on 0.7PbMg(1/3)Nb(2/3)O3-0.3PbTiO3 (PMN-PT) substrates. The electric transport properties of the Co-C films were effectively modulated by...

2006
Shaoxin Lu Balaji Panchapakesan

In this paper we report for the first time, the photoconductivity of large area sheets of single wall carbon nanotube upon laser illumination. The photoconductivity exhibited an increase, decrease or even ‘negative’ values when the laser spot was on different positions between contact electrodes, showing a ‘position’ dependent effect of photoconductivity. Photon induced charge carrier generatio...

Journal: :Physical review letters 2014
A J Frenzel C H Lui Y C Shin J Kong N Gedik

We investigate the transient photoconductivity of graphene at various gate-tuned carrier densities by optical-pump terahertz-probe spectroscopy. We demonstrate that graphene exhibits semiconducting positive photoconductivity near zero carrier density, which crosses over to metallic negative photoconductivity at high carrier density. These observations can be accounted for by the interplay betwe...

2016
R. Mathur A. Kumar

Temperature and intensity dependence of steady state photoconductivity is studied in amorphous thin films of Ge22Se68Bi10 prepared by vacuum evaporation. Photoconductivity increases exponentially with temperature between 310 K and 410 K and no maxima is found in this temperature range. The ratio Iph/Id is about 6 at 310 K and decreases continuously as temperature is increased. Photoconductivity...

2013
Edward Deveney Peter K. LeMaire

This study explores the effect of Ag+ ions on transient photoconductivity of thin films of Se75Te20Ag5. The thin films of Se75Te20Ag5 chalcogenide alloys were made by evaporation method using a vacuum chamber at HBTI Kanpur, India. This amorphous system showed the presence of negative photocurrent when white light was stopped showing on the sample. The rise and decay of photoconductivity was ob...

2008
J. P. Kotthaus

We investigate the Terahertz(THz)-response of a square antidot superlattice by means of photoconductivity measurements using a Fourier-transformspectrometer. We detect, spectrally resolved, the cyclotron resonance and the fundamental magnetoplasmon mode of the periodic superlattice. In the dissipative transport regime both resonances are observed in the photoresponse. In the adiabatic transport...

2016
A. S. Maan D. R. Goyal A. Kumar

2014 Present communication reports on photoconductivity measurements in thin films of Ga40SexTe60-x glasses (x = 20, 30, 40). Temperature dependence of steady state photocurrent and dark current show that dark and steady state photoconductivity are activated processes. Intensity dependence of photocurrent reveals about power law dependence of photocurrent on incident radiation. Also incorporate...

2014
T. DeBorde E. D. Minot

We utilize photoconductivity spectroscopy to identify the unique chiral structure of individual carbon nanotubes (CNTs). Peaks in photoconductivity are measured throughout the visible and near-IR wavelength ranges. Photoconductivity peaks associated with individual CNTs are referenced against existing Rayleigh scattering measurements to uniquely identify chiral indices. We find close agreement ...

1997
A. Hoffmann Ivan K. Schuller M. G. Medici P. Seidel

We observed persistent photoconductivity in YBa2Cu3Ox bicrystal grain boundary Josephson junctions. Upon illumination of these grain boundary Josephson junctions, the normal state resistance decreases and the critical current increases. This strongly suggests that the grain boundary in these films consists of oxygen depleted YBa2Cu3Ox . A comparison with the persistent photoconductivity in oxyg...

2016
Hongwei Liu Junpeng Lu Zongyin Yang Jinghua Teng Lin Ke Xinhai Zhang Limin Tong Chorng Haur Sow

Superiorly high photoconductivity is desirable in optoelectronic materials and devices for information transmission and processing. Achieving high photoconductivity via bandgap engineering in a bandgap-graded semiconductor nanowire has been proposed as a potential strategy. In this work, we report the ultrahigh photoconductivity of bandgap-graded CdSxSe1-x nanowires and its detailed analysis by...

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