Terahertz photoconductivity of mobile electrons in nanoporous InP honeycombs

Nanostructured semiconductors with favorable optoelectronic properties can be created by electrochemical etching, a fabrication process that is scalable for mass market applications. Using terahertz photoconductivity measurements, we demonstrate that nanoporous InP has an unusually long carrier recombination lifetime that exceeds 100 ns at low temperatures and low carrier density, and an electron mobility half that of bulk InP. Modeling confirms that these observations result from band bending with holes confined to the surface and electrons away from the pores.

[1]  Joshua E. Goldberger,et al.  SEMICONDUCTOR NANOWIRES AND NANOTUBES , 2004 .

[2]  Matthew C. Beard,et al.  Carrier Localization and Cooling in Dye-Sensitized Nanocrystalline Titanium Dioxide , 2002 .

[3]  Hans L. Hartnagel,et al.  Semiconductor sieves as nonlinear optical materials , 2000 .

[4]  D. Grischkowsky,et al.  Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors , 1990 .

[5]  C. Jagadish,et al.  Photoluminescence study of the dynamical properties of GaAs sawtooth superlattices , 1997 .

[6]  C. Jagadish,et al.  Influence of surface passivation on ultrafast carrier dynamics and terahertz radiation generation in GaAs , 2006, cond-mat/0610567.

[7]  Matthew C. Beard,et al.  Size-Dependent Photoconductivity in CdSe Nanoparticles as Measured by Time-Resolved Terahertz Spectroscopy , 2002 .

[8]  Chennupati Jagadish,et al.  Transient Terahertz Conductivity of GaAs Nanowires , 2007 .

[9]  Sir Nevill Mott.  Electrons in glass , 1978 .

[10]  M. Bonn,et al.  Exciton polarizability in semiconductor nanocrystals , 2006, Nature materials.

[11]  W. Chou,et al.  Built-in electric field and surface Fermi level in InP surface-intrinsic n+ structures by modulation spectroscopy , 1997 .

[12]  Yasuo Takahashi,et al.  Detection of single charges and their generation-recombination dynamics in Si nanowires at room temperature , 2002 .

[13]  David G. Cooke,et al.  Transient terahertz conductivity in photoexcited silicon nanocrystal films , 2006 .

[14]  P Lunkenheimer,et al.  Response of disordered matter to electromagnetic fields. , 2003, Physical review letters.

[15]  Charles A Schmuttenmaer,et al.  Exploring dynamics in the far-infrared with terahertz spectroscopy. , 2004, Chemical reviews.

[16]  Shashank Sharma,et al.  Surface Charge Density of Unpassivated and Passivated Metal-Catalyzed Silicon Nanowires , 2006 .

[17]  Ion Tiginyanu,et al.  Enhanced nonlinear optical response of InP(100) membranes , 2005 .

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

[19]  J. Lloyd-Hughes,et al.  Conductivity of nanoporous InP membranes investigated using terahertz spectroscopy , 2007, LEOS 2008 - 21st Annual Meeting of the IEEE Lasers and Electro-Optics Society.

[20]  W. Walukiewicz,et al.  Electron mobility and free‐carrier absorption in InP; determination of the compensation ratio , 1979 .

[21]  R. H. M. Groeneveld,et al.  Picosecond time-resolved far-infrared experiments on carriers and excitons in GaAs–AlGaAs multiple quantum wells , 1994 .

[22]  Charles M. Lieber,et al.  High Performance Silicon Nanowire Field Effect Transistors , 2003 .

[23]  David A. Ritchie,et al.  Terahertz magnetoconductivity of excitons and electrons in quantum cascade structures , 2008 .

[24]  Paul K. L. Yu,et al.  Influence of surface states on the extraction of transport parameters from InAs nanowire field effect transistors , 2007 .

[25]  H. Hosono,et al.  Observation of Jonscher law in ac hopping conduction of the electron-doped nanoporous crystal 12CaO·7Al2O3 in a THz frequency range , 2004 .

[26]  D. Chemla,et al.  Ultrafast terahertz probes of transient conducting and insulating phases in an electron–hole gas , 2003, Nature.

[27]  Ion Tiginyanu,et al.  Pores in III–V Semiconductors , 2003 .