Time-Resolved Microwave Photoconductivity (TRMC) Using Planar Microwave Resonators: Application to the Study of Long-Lived Charge Pairs in Photoexcited Titania Nanotube Arrays

Steady-state (SRMC) and time-resolved microwave photoconductivity (TRMC) are key techniques used to perform the contact-less determination of carrier density, transport, trapping, and recombination parameters in charge transport materials such as organic semiconductors and dyes, inorganic semiconductors, and metal–insulator composites, which find use in conductive inks, thin film transistors, light-emitting diodes, photocatalysts, and photovoltaics. We present the theory, design, simulation, and fabrication of a planar microwave ring resonator operating at 5.25 GHz with a quality factor of 224, to perform SRMC and TRMC measurements. Our method consists of measuring the resonance frequency (f0) and Q-factor of the microwave resonator with the sample to be probed placed in a defined sensitive region of the resonator where the microwave field is highly concentrated. We also provide proof of concept measurements of the time-resolved microwave photoresponse of anatase-phase TiO2 nanotube array membranes (TNTAM...

[1]  K. Shankar,et al.  Electron Transport, Trapping and Recombination in Anodic TiO 2 Nanotube Arrays , 2015 .

[2]  R. Adelung,et al.  Integration of individual TiO2 nanotube on the chip: Nanodevice for hydrogen sensing , 2015 .

[3]  Mojgan Daneshmand,et al.  Detection of Volatile Organic Compounds Using Microwave Sensors , 2015, IEEE Sensors Journal.

[4]  N. Hoivik,et al.  Photoconductivity of Au-coated TiO2 nanotube arrays , 2014, 14th IEEE International Conference on Nanotechnology.

[5]  Somnath C. Roy,et al.  Water assisted crystallization, gas sensing and photo-electrochemical properties of electrochemically synthesized TiO2 nanotube arrays , 2014 .

[6]  P. Kužel,et al.  THz photoconductivity in light-emitting surface-oxidized Si nanocrystals: the role of large particles , 2014 .

[7]  D. Fermín,et al.  Density of Deep Trap States in Oriented TiO2 Nanotube Arrays , 2014 .

[8]  C. Colbeau-Justin,et al.  Preservation of the photocatalytic activity of TiO2 by EDTA in the reductive transformation of Cr(VI). Studies by Time Resolved Microwave Conductivity , 2014 .

[9]  F. Palma,et al.  Microwave sensing of nanostructured semiconductor surfaces , 2014 .

[10]  C. Colbeau-Justin,et al.  TiO2-photocatalytic transformation of Cr(VI) in the presence of EDTA: Comparison of different commercial photocatalysts and studies by Time Resolved Microwave Conductivity , 2014 .

[11]  J. McCloy,et al.  Regenerative feedback resonant circuit to detect transient changes in electromagnetic properties of semi-insulating materials. , 2013, The Review of scientific instruments.

[12]  G. Shao,et al.  Numerical study of metal oxide hetero-junction solar cells with defects and interface states , 2013 .

[13]  T. Savenije,et al.  What Limits Photoconductance in Anatase TiO2 Nanostructures? A Real and Imaginary Microwave Conductance Study , 2013 .

[14]  H. Jakobsen,et al.  Photoconductive, free-standing crystallized TiO2 nanotube membranes , 2013 .

[15]  H. Cachet,et al.  Relation between morphology and conductivity in TiO2 nanotube arrays: an electrochemical impedance spectrometric investigation , 2013, Journal of Solid State Electrochemistry.

[16]  K. Shankar,et al.  Photocatalytic conversion of diluted CO2 into light hydrocarbons using periodically modulated multiwalled nanotube arrays. , 2012, Angewandte Chemie.

[17]  A. Walker,et al.  In situ detection of free and trapped electrons in dye-sensitized solar cells by photo-induced microwave reflectance measurements , 2012 .

[18]  F. J. Knorr,et al.  Observation of charge transport in single titanium dioxide nanotubes by micro-photoluminescence imaging and spectroscopy. , 2012, ACS nano.

[19]  Laxmikant V. Saraf,et al.  Location Of Hole And Electron Traps On Nanocrystalline Anatase TiO2 , 2012 .

[20]  S. Kasap,et al.  The origin of non-Drude terahertz conductivity in nanomaterials , 2012 .

[21]  H. Jakobsen,et al.  Progress on free-standing and flow-through TiO2 nanotube membranes , 2012 .

[22]  Sheikh A. Akbar,et al.  A selective room temperature formaldehyde gas sensor using TiO2 nanotube arrays , 2011 .

[23]  K. Domen,et al.  Spontaneous phase and morphology transformations of anodized titania nanotubes induced by water at room temperature. , 2011, Nano letters.

[24]  Joan Daniel Prades,et al.  On the photoconduction properties of low resistivity TiO2 nanotubes , 2010, Nanotechnology.

[25]  Charles A Schmuttenmaer,et al.  Exciton-like trap states limit electron mobility in TiO2 nanotubes. , 2010, Nature nanotechnology.

[26]  G. Boschloo,et al.  Comparison of trap-state distribution and carrier transport in nanotubular and nanoparticulate TiO(2) electrodes for dye-sensitized solar cells. , 2010, Chemphyschem : a European journal of chemical physics and physical chemistry.

[27]  N. Marzari,et al.  Ultraviolet Photodetectors Based on Anodic TiO2 Nanotube Arrays , 2010 .

[28]  Jinghong Li,et al.  Biofunctional titania nanotubes for visible-light-activated photoelectrochemical biosensing. , 2010, Analytical chemistry.

[29]  T. Savenije,et al.  Highly Photoconductive CdSe Quantum-Dot Films: Influence of Capping Molecules and Film Preparation Procedure , 2010 .

[30]  Craig A Grimes,et al.  Long vertically aligned titania nanotubes on transparent conducting oxide for highly efficient solar cells. , 2009, Nature nanotechnology.

[31]  Craig A. Grimes,et al.  High-rate solar photocatalytic conversion of CO2 and water vapor to hydrocarbon fuels. , 2009, Nano letters.

[32]  Alison B. Walker,et al.  Dye-sensitized solar cells based on oriented TiO2 nanotube arrays: transport, trapping, and transfer of electrons. , 2008, Journal of the American Chemical Society.

[33]  Andrei Ghicov,et al.  Self-organized, free-standing TiO2 nanotube membrane for flow-through photocatalytic applications. , 2007, Nano letters.

[34]  C. Grimes,et al.  Initial Studies on the Hydrogen Gas Sensing Properties of Highly-Ordered High Aspect Ratio TiO 2 Nanotube-Arrays 20 μ m to 222 μ m in Length , 2006 .

[35]  J. Yates,et al.  Light-induced charge separation in anatase TiO2 particles. , 2005, The journal of physical chemistry. B.

[36]  J. Warman,et al.  Electrodeless time-resolved microwave conductivity study of charge-carrier photogeneration in regioregular poly(3-hexylthiophene) thin films , 2004 .

[37]  A. Yamazaki,et al.  Superior Schottky electrode of RuO2 for deep level transient spectroscopy on anatase TiO2 , 2003 .

[38]  Steven H. Szczepankiewicz,et al.  Slow Surface Charge Trapping Kinetics on Irradiated TiO2 , 2002 .

[39]  N. V. Smith,et al.  Classical generalization of the Drude formula for the optical conductivity , 2001 .

[40]  S. Studenikin,et al.  Effect of oxygen on transient photoconductivity in thin-film Nb x Ti 1¿x O 2 , 2000 .

[41]  M. Paganini,et al.  Generation of superoxide ions at oxide surfaces , 1999 .

[42]  S. Studenikin,et al.  Spray pyrolysis preparation of porous polycrystalline thin films of titanium dioxide containing Li and Nb , 1999 .

[43]  S. Studenikin,et al.  Density of band-gap traps in polycrystalline films from photoconductivity transients using an improved Laplace transform method , 1998 .

[44]  R. W. Fessenden,et al.  Rate Constants for Charge Injection from Excited Sensitizer into SnO2, ZnO, and TiO2 Semiconductor Nanocrystallites , 1995 .

[45]  S. Martin,et al.  Time-resolved microwave conductivity. Part 2.—Quantum-sized TiO2 and the effect of adsorbates and light intensity on charge-carrier dynamics , 1994 .

[46]  S. Martin,et al.  Time-resolved microwave conductivity. Part 1.—TiO2 photoreactivity and size quantization , 1994 .

[47]  G. Beck,et al.  The study of charge carrier kinetics in semiconductors by microwave conductivity measurements. II. , 1986 .

[48]  R. W. Fessenden,et al.  Photosensitized charge injection into TiO2 particles as studied by microwave absorption , 1986 .

[49]  J. Warman,et al.  Photon-induced molecular charge separation studied by nanosecond time-resolved microwave conductivity , 1982 .

[50]  R. W. Fessenden,et al.  Measurement of the dipole moments of excited states and photochemical transients by microwave dielectric absorption , 1982 .

[51]  N. H. March,et al.  High Frequency Conductivity in Semiconductors , 1956 .

[52]  W. Shockley,et al.  Microwave Observation of the Collision Frequency of Electrons in Germanium , 1953 .