Ultrafast terahertz photoconductivity in nanocrystalline mesoporous TiO2 films

Němec, H.; Kuzžel, P.; Kadlec, F.; Fattakhova-Rohlfing, D.; Szeifert, J.; Bein, T.; Kalousek, V.; Rathouský, J.
February 2010
Applied Physics Letters;2/8/2010, Vol. 96 Issue 6, p062103
Academic Journal
Terahertz time-resolved spectroscopy is used to investigate the transport of photoexcited electrons in nanocrystalline mesoporous TiO2 films prepared by the recently proposed “brick and mortar” technology [Szeifert et al.Chem. Mater. 21, 1260 (2009)] with a variable fraction of nanocrystalline titania “bricks” and amorphous titania “mortar.” Both long- and short-range conductivity is significantly enhanced upon calcination. After an ultrafast (subpicosecond) regime where the intrananograin conductivity dominates, the electron conductivity becomes limited by the interaction of electrons with the amorphous mortar. Comparison of the experimental results with Monte Carlo simulations of the electron motion allows us to determine the crystalline grain size after calcination and the yield of mobile photocarriers.


Related Articles

  • Two-band k · p model for Si-(110) electron devices. Donetti, Luca; Gámiz, Francisco; Biel, Blanca; Sampedro, Carlos // Journal of Applied Physics;Aug2013, Vol. 114 Issue 7, p073706 

    Carrier transport in Si-(110) surfaces is a topic of growing interest because of its presence in the lateral interfaces of vertical structures, such as FinFETs or tri-gate devices. It has been shown that the parabolic effective mass model cannot explain the experimental behavior of electron...

  • Substrate-induced order in confined nematic liquid-crystal films. Gruhn, Thomas; Schoen, Martin // Journal of Chemical Physics;6/1/1998, Vol. 108 Issue 21, p9124 

    Examines the microscopic structure of liquid-crystalline films confined between two solid surfaces consisting of Nitrogen atoms. Use of grand canonical ensemble Monte Carlo simulations; Change from a planar orientation to a perpendicular orientation in molecules; Manifestation of orientational...

  • High-frequency behavior of the Datta–Das spin transistor. López, H.; Oriols, X.; Suñé, J.; Cartoixà, X. // Applied Physics Letters;11/10/2008, Vol. 93 Issue 19, p193502 

    We have studied the high-frequency behavior and the ultimate limiting factor to the cutoff frequency for the Datta–Das spin transistor using device Monte Carlo simulations. We have found that the maximum frequency of operation is not related to intrinsic parameters to the spin of the...

  • Terahertz oscillations in an In0.53Ga0.47As submicron planar Gunn diode. Khalid, Ata; Dunn, G. M.; Macpherson, R. F.; Thoms, S.; Macintyre, D.; Li, C.; Steer, M. J.; Papageorgiou, V.; Thayne, I. G.; Kuball, M.; Oxley, C. H.; Montes Bajo, M.; Stephen, A.; Glover, J.; Cumming, D. R. S. // Journal of Applied Physics;2014, Vol. 115 Issue 11, p114502-1 

    The length of the transit region of a Gunn diode determines the natural frequency at which it operates in fundamental mode-the shorter the device, the higher the frequency of operation. The long-held view on Gunn diode design is that for a functioning device the minimum length of the transit...

  • Monte-Carlo-based spectral gain analysis for terahertz quantum cascade lasers. Jirauschek, Christian; Lugli, Paolo // Journal of Applied Physics;Jun2009, Vol. 105 Issue 12, p123102-1 

    Employing an ensemble Monte Carlo transport simulation, we self-consistently analyze the spectral gain for different terahertz quantum cascade laser structures, considering bound-to-continuum as well as resonant phonon depopulation designs. In this context, we investigate temperature dependent...

  • Shot noise in metallic double dot structures with a negative differential conductance. Nguyen, V. Hung; Nguyen, V. Lien; Dollfus, Philippe // Applied Physics Letters;9/19/2005, Vol. 87 Issue 12, p123107 

    The shot noise of current through a metallic double quantum dot structure exhibiting negative differential conductance is studied. We can exactly solve the master equation and derive an analytical expression of the spectral density of current fluctuations as a function of frequency in the first...

  • Formally exact path integral Monte Carlo calculations using approximate projection operators. Hall, Randall W. // Journal of Chemical Physics;11/1/1992, Vol. 97 Issue 9, p6481 

    A class of approximate projection operators is used to reduce the variance in path integral Monte Carlo calculations in a formally exact manner. Paths are classified according to the projection operators, allowing the identification of paths whose contribution to the variance is negligible. The...

  • Correlated electron extracule densities in position and momentum spaces. Galvez, F.J.; Buendia, E.; Sarsa, A. // Journal of Chemical Physics;8/22/1999, Vol. 111 Issue 8, p3319 

    Studies the correlated electron extracule densities in position and momentum spaces. Use of the Monte Carlo method to deal with the integrals involved in the calculation of two electron densities; Functional form of the wave functions; Computational method used to calculate the different...

  • Monte Carlo simulation of transverse electron focusing. Hornsey, R. I. // Journal of Applied Physics;1/15/1996, Vol. 79 Issue 2, p832 

    Presents a study which developed a Monte Carlo simulation for transverse electron focusing to allow the investigation of the individual and combined effects of injector and collector widths, specularity efficient, injection divergence angle, and electron mean free path. Background on transverse...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics