One-dimensional hole gas in germanium silicon nanowire hetero-structures Linyou Cao Department of Materials Science and Engineering

One-dimensional hole gas in germanium silicon nanowire hetero-structures

• Linyou Cao

• Department of Materials Science and Engineering

• Drexel University

• 12/09/2005

Motivation-Why?

• Quantum Confinement not reported in NW

• Ballistic Transport
• Conductance Quantification

• Controlled synthesis of NW offering substantial potential to engineer in 1-D electronic system

• Band-gap engineering in hetero-system widely used in semiconductor technique

Si/Ge NW

Chemical Vapor Deposition

Fabrication of Devices

Ballistic Transport-Conception

Conclusion

• Create a 1D hole gas system in Ge/Si core/shell NW heterostructures.

• Ballistic transport through individual 1D subbands due to confinement of carriers in the radial direction

• Little temperature dependence, suggesting a room temperature carrier mean free path on the order of several hundred nanometers

Questions:

• Physical model for Ge/Si,

• the effect of depletion thickness of Ge/Si??
• Effect of radial size of Ge/Si
• Effect of spin polarization??

• Theoretical Explanation for Ballistic Transport in Si/Ge??

What we can do??

• 1-D Electron Gas, inverse Ge/Si??

• Controlled 1-D gas via external field, like Quantum Hall Effect

• Compound Semiconductor Hetero-Junction??

• Multi-layer Junction to make coupled hole-electron,hole-hole,electron-electron gas??

• Bipolar transistor, like Optic-electronic

Thanks