Effect of anomalous diffusion of fluctuating Cooper pairs on the density of states of superconducting NbN thin films

Electron transport in vacuum-deposited a-Se films with thicknesses varying from 13 to 501 μm has been investigated by conventional time-of-flight (TOF) and interrupted field TOF experiments. To separate the influences of electric field and the thickness, all TOF experiments were performed at a constant electric field. It has been found that the electron mobility is relatively constant in thick films (L > 50 μm) and increases in thinner films (L < 50 μm) with decreasing thickness. On the other hand, the electron lifetime is relatively thickness independent in films with thickness L > 50 μm, but drops sharply in thin films when L < 50 μm. These observations can be explained based on the density of states model that includes three types of traps forming Gaussian-like distributions within the mobility gap as reported in Koughia et al. (J. Appl. Phys. 97, 033706 (2005)).

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Vibrational density of states of thin films measured by inelastic scattering of synchrotron radiation

Physica B Condensed Matter ◽

10.1016/s0921-4526(98)01259-9 ◽

1999 ◽

Vol 263-264 ◽

pp. 581-583 ◽

Cited By ~ 16

Author(s):

R Röhlsberger ◽

W Sturhahn ◽

T.S Toellner ◽

K.W Quast ◽

E.E Alp ◽

...

Keyword(s):

Thin Films ◽

Synchrotron Radiation ◽

Inelastic Scattering ◽

Density Of States ◽

Vibrational Density Of States ◽

Vibrational Density

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Quasiparticle density of states in a half metal in the presence of odd-frequency Cooper pairs

physica status solidi (a) ◽

10.1002/pssa.200776451 ◽

2008 ◽

Vol 205 (5) ◽

pp. 1023-1025 ◽

Cited By ~ 2

Author(s):

Yasuhiro Asano ◽

Takehito Yokoyama ◽

Yukio Tanaka ◽

Alexander A. Golubov

Keyword(s):

Density Of States ◽

Cooper Pairs ◽

Half Metal ◽

Quasiparticle Density

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Density of States of Amorphous Germanium Thin Films Deposited by the Pecvd of H2-Diluted Germane

MRS Proceedings ◽

10.1557/proc-192-163 ◽

1990 ◽

Vol 192 ◽

Cited By ~ 6

Author(s):

C. Godet ◽

V. Chu ◽

B. Equer ◽

Y. Bouizem ◽

L. Chahed ◽

...

Keyword(s):

Thin Films ◽

Density Of States ◽

Surface Passivation ◽

Defect Density ◽

Level Density ◽

Chemical Vapor ◽

Optical Data ◽

Hydrogen Atoms ◽

Bond Density ◽

Spin Measurements

ABSTRACTThe disorder in a-Ge:H thin films produced by the plasma-enhanced chemical vapor deposition (PECVD) technique is strongly reduced when the GeH4 gas is diluted at 1% in H2 and the radiofrequency power density is increased to 0.1 W.cm−2. This improvement is attributed to a better surface passivation by the hydrogen atoms during the growth. However, the poor transport properties indicate a still high defect density. The midgap defect absorption and the Urbach energy, obtained from the photothermal deflection spectra calibrated with optical data, both decrease as a function of the film thickness. The optical defect density is calibrated with EPR spin measurements. For a-Ge:H films thicker than 2 μm, obtained at a deposition temperature Ts ranging from 150 to 250°C, the Urbach tail parameter E° is lower than 50 meV and not sensitive to Ts ; the dangling bond density is around 4.107 cm−3, which is higher by a factor of 100 than in a-Si:H. Preliminary transport measurements indicate that the Fermi level density of states is larger than 1018 cm−3.eV−1.

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