Dependence of photocurrent in single-crystalline boron nanobelts on atmosphere

This letter describes the dependence of photocurrent of single-crystalline boron nanobelts on the atmosphere. In ambient air, slow photoresponse under blue light illumination was observed. Rise and decay times exceeded three days. The magnitude of photoresponse in ambient air and oxygen was greater than that in hydrogen and argon atmospheres. In vacuum, a photoresistivity effect consisting of the continuous decrease of conductance under blue light illumination was observed. Variation of band bending of the nanobelt surface by adsorption or desorption of oxygen and water molecules appeared to switch the photoconduction on and off by the respective trapping and recombination of photoexcited carriers at the nanobelt core and surface.This letter describes the dependence of photocurrent of single-crystalline boron nanobelts on the atmosphere. In ambient air, slow photoresponse under blue light illumination was observed. Rise and decay times exceeded three days. The magnitude of photoresponse in ambient air and oxygen was greater than that in hydrogen and argon atmospheres. In vacuum, a photoresistivity effect consisting of the continuous decrease of conductance under blue light illumination was observed. Variation of band bending of the nanobelt surface by adsorption or desorption of oxygen and water molecules appeared to switch the photoconduction on and off by the respective trapping and recombination of photoexcited carriers at the nanobelt core and surface.

[1]  H. Werheit,et al.  New pecularities of the conductivity and photoconductivity mechanisms in β-rhombohedral boron , 2004 .

[2]  R. Schmechel,et al.  Correlation between structural defects and electronic properties of icosahedral boron-rich solids , 1999 .

[3]  K. Kimura,et al.  Thermoelectric Properties of Metal-Doped β-Rhombohedral Boron , 2000 .

[4]  W. Lau,et al.  X-ray photoemission spectroscopy of nonmetallic materials: Electronic structures of boron and BxOy , 2004 .

[5]  R. Schmechel,et al.  Photoluminescence and Steady-State Interband Photoconductivity of High-Purity β-Rhombohedral Boron , 2000 .

[6]  Kenji Kawaguchi,et al.  Temperature dependence of electrical conductance in single-crystalline boron nanobelts , 2005 .

[7]  H. Werheit,et al.  Interband and Gap State Related Transitions in β‐Rhombohedral Boron , 1993 .

[8]  H. Werheit,et al.  Jahn-Teller Effect of the B12 Icosahedron and Its General Influence on the Valence Band Structures of Boron-Rich Solids , 1989 .

[9]  A. Fujiwara,et al.  Li- and Mg-doping into Icosahedral Boron Crystals, α- and β- Rhombohedral Boron, Targeting High-Temperature Superconductivity: Structure and Electronic States , 2004 .

[10]  Superconductivity from doping boron icosahedra , 2003, cond-mat/0312200.

[11]  Rodney S. Ruoff,et al.  Crystalline Boron Nanoribbons: Synthesis and Characterization , 2004 .

[12]  William E. Buhro,et al.  Electrical transport in boron nanowires , 2003 .

[13]  D. Emin,et al.  A proposed boron-carbide-based solid-state neutron detector , 2005 .

[14]  Ching,et al.  Electronic structures, total energies, and optical properties of alpha -rhombohedral B12 and alpha -tetragonal B50 crystals. , 1992, Physical review. B, Condensed matter.

[15]  Kenji Kawaguchi,et al.  Catalyst-free fabrication of single crystalline boron nanobelts by laser ablation , 2003 .

[16]  Z. Wang,et al.  Nanowires and nanobelts : materials, properties, and devices , 2006 .

[17]  Kenji Kawaguchi,et al.  Electrical transport of tetragonal boron nanobelts , 2005 .

[18]  Kenji Kawaguchi,et al.  Mg-doping experiment and electrical transport measurement of boron nanobelts , 2006 .

[19]  D. Rowe.  CRC Handbook of Thermoelectrics , 1995 .