Semiconductor Nanowire-Based Devices and Systems

Background

The bottom up approach of integrating nanowires offers the ability to effectively scale devices dimensions into the low nano range. It won't be long before top down approaches such as photolithography reach a critical size limit. We take advantage of the recently demonstrated novel bridging technique of nanowires across a trench [1]. The wires are epitaxially bridged with continuous single crystalline ohmic junctions grown using the vapor liquid solid technique [2]. Previously, metal electrodes were deposited onto the ends of a nanowire creating non-linear (Schottky type contacts) between the two dissimilar materials. The epitaxially bridged nanowire based devices can be easily integrated into current conventional IC's.

Research Focus

Our group's interest includes the exploration of novel devices utilizing Si, SiGe and SiGeC based nanowires. Materials such as InP and ZnO are also being explored in the hopes of creating novel photonic nanowire devices. Complete characterization of the nanowire's, electrical, mechanical, optical and piezoelectric properties are of great interest to us as well. Several metals have been used as the catalysts with growth temperatures at ~650°C. The high temperature process is not compatible with existing IC fabrication processes. So, alternative catalyst materials are being explored in hopes of reducing the nanowire growth temperature. Both the surface states and the dopant profile define the electrical and the optical properties of the nanowires. The dopant profile information is needed to design sensors, transistors, etc. Our eventual goal is to explore novel device applications of semiconductor nanowires with an in-depth understanding of material characteristics.

More Information on Nanowire Devices

  • Device design and fabrication
  • Device modeling and characterization
  • Precise positioning of nanowires
  • Nanowire sensors
  • Nanowires for negative index materials
  • Nanowire devices grown on any kind of substrate
  • Highly efficient and low cost solar cells
  • Nanowire-biological interfaces

Documents

Collaborators

  • Hewlett-Packard Labs
  • Agilent Labs
  • Sandia National Labs
  • U Conn
  • AFSOR
  • U Florida
  • Banpil Photonics

Research Sponsors

  • NSF (CMMI Division)
  • Hewlett-Packard Labs
  • Agilent Labs
  • DARPA
  • CITRIS.

References

  1. M. Saif. Islam, S. Sharma, T.I. Kamins, R.S. Williams, "Ultrahigh-density silicon nanobridges formed between two vertical silicon surfaces", Nanotechnology 15 (2004) L5–L8.
  2. M. Saif Islam, S. Sharma, T. I. Kamins, and R. Stanley Williams, "A novel interconnection technique for manufacturing nanowire devices", Applied Physics A: Special Issue on Nanotechnology, 80 , (6), pp 1133-1140, (2005).
  3. S. Sharma, T. I. Kamins, M. Saif Islam, and R. Stanley Williams, "Structural characteristics and connection mechanism of gold-catalyzed bridging silicon nanowires", Journal of Crystal Growth 280 (2005) 562–568
  4. Jong Soo Lee, M. Saif Islam , and Sangtae Kim "Photoresponses of ZnO nanobridge devices fabricated using a single–step thermal evaporation method", accepted for publication in Sensors & Actuators: B. Chemical, 2006 (10.1016/j.snb.2006.10.042).
  5. Sung Soo Yi, G. Girolami, Jun Amano and S. Sharma, T. I. Kamins, I. Kimukin, M. Saif Islam , "InP nanobridges epitaxially formed between two vertical Si surfaces by metal-catalyzed chemical vapor deposition", Applied Phys. Letters, 89, 133121, 2006.
  6. Jong Soo Lee, M. Saif Islam , and Sangtae Kim, "Direct formation of catalyst-free ZnO nanobridges on an etched Si substrate using a thermal evaporation method", Nano Letters, Vol. 6, No. 7 p1487 2006.
  7. S. Reza, G. Bosman, M. Saif Islam , T. I. Kamins, S. Sharma and R. Stanley Williams, "Noise in Si Nanowires", Accepted for publication in IEEE Trans. Nanotechnology, 5, No. 5, p523 2006.
  8. Kimukin, M. Saif Islam and R. Stanley Williams, "Surface depletion thickness of p-doped Si nanowires grown using metal-catalysed chemical vapour deposition", Nanotechnology 17 (2006) S1-S6.
  9. Massood Tabib-Azar, Maissarath Nassirou, Run Wang, S. Sharma, T. I. Kamins, M. Saif Islam , and R. Stanley Williams, "Mechanical properties of self-welded silicon nanobridges", Applied Phys. Letters, 87, 113102, (2005).
  10. A. Choudhry, and M. Saif Islam , "Examining the anomalous resistance observed for InN nanowires", submitted to Journal of Nanoscience and Nanotechnology, 2007.
  11. A. Choudhry, Vishwanath Ramamurthi, Erin Fong and M. Saif Islam , "Ultra-low contact resistance of epitaxially interfaced Si nanowires, Accepted Nanoletters. 2007.