Direct measurement of individual deep traps in single silicon nanowires.

The potential of the metal nanocatalyst to contaminate vapor-liquid-solid (VLS) grown semiconductor nanowires has been a long-standing concern, since the most common catalyst material, Au, is known to induce deep gap states in several semiconductors. Here we use Kelvin probe force microscopy to image individual deep acceptor type trapping centers in single undoped Si nanowires grown with an Au catalyst. The switching between occupied and empty trap states is reversibly controlled by the back-gate potential in a nanowire transistor. The trap energy level, i.e., E(C) - E(T) = 0.65 ± 0.1 eV was extracted and the concentration was estimated to be ∼2 × 10(16) cm(-3). The energy and concentration are consistent with traps resulting from the unintentional incorporation of Au atoms during the VLS growth.

[1]  Shui-Tong Lee,et al.  Transmission electron microscopy evidence of the defect structure in Si nanowires synthesized by laser ablation , 1998 .

[2]  C. Ni,et al.  Instability and transport of metal catalyst in the growth of tapered silicon nanowires. , 2006, Nano letters.

[3]  Volker Schmidt,et al.  Silicon Nanowires: A Review on Aspects of their Growth and their Electrical Properties , 2009, Advanced materials.

[4]  C. B. Collins,et al.  Properties of Gold-Doped Silicon , 1957 .

[5]  R. S. Wagner,et al.  VAPOR‐LIQUID‐SOLID MECHANISM OF SINGLE CRYSTAL GROWTH , 1964 .

[6]  Yossi Rosenwaks,et al.  Kelvin probe force microscopy of semiconductor surface defects , 2004 .

[7]  Hans J. Queisser,et al.  Recombination at deep traps , 1978 .

[8]  Y. Miyamoto,et al.  Role of Agents in Filamentary Growth of Amorphous Silicon , 1976 .

[9]  E Koren,et al.  Obtaining uniform dopant distributions in VLS-grown Si nanowires. , 2011, Nano letters.

[10]  Peng Wang,et al.  High-resolution detection of Au catalyst atoms in Si nanowires. , 2008, Nature nanotechnology.

[11]  H. Kumar Wickramasinghe,et al.  High‐resolution capacitance measurement and potentiometry by force microscopy , 1988 .

[12]  A. Stemmer,et al.  Resolution and contrast in Kelvin probe force microscopy , 1998 .

[13]  S. Senz,et al.  UHV chemical vapour deposition of silicon nanowires , 2005 .

[14]  K. A. Jackson,et al.  Study of the Filamentary Growth of Silicon Crystals from the Vapor , 1964 .

[15]  Yossi Rosenwaks,et al.  Nonuniform doping distribution along silicon nanowires measured by Kelvin probe force microscopy and scanning photocurrent microscopy , 2009 .

[16]  M. Spencer,et al.  Cantilever effects on the measurement of electrostatic potentials by scanning Kelvin probe microscopy , 2001 .

[17]  Dhananjay Kumar,et al.  Point defect configurations of supersaturated Au atoms inside Si nanowires. , 2008, Nano letters.

[18]  V. Nebol'sin,et al.  Role of Surface Energy in the Vapor–Liquid–Solid Growth of Silicon , 2003 .

[19]  Yossi Rosenwaks,et al.  Measurement of active dopant distribution and diffusion in individual silicon nanowires. , 2010, Nano letters.

[20]  H. Grimmeiss,et al.  Deep Level Impurities in Semiconductors , 1977 .

[21]  U. Gösele,et al.  On the formation of Si nanowires by molecular beam epitaxy , 2006 .

[22]  J. Tersoff,et al.  Sawtooth faceting in silicon nanowires. , 2005, Physical review letters.

[23]  S. Kodambaka,et al.  Control of Si nanowire growth by oxygen. , 2006, Nano letters.

[24]  S. Hudlet,et al.  Evaluation of the capacitive force between an atomic force microscopy tip and a metallic surface , 1998 .

[25]  Charles M. Lieber,et al.  A laser ablation method for the synthesis of crystalline semiconductor nanowires , 1998, Science.

[26]  E. I. Givargizov.  Fundamental aspects of VLS growth , 1975 .