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Surface segregation and backscattering in doped silicon nanowires.
M V Fernández-Serra1, Ch Adessi, X Blase
1Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), UMR CNRS 5586, Université Claude Bernard Lyon 1, Bâtiment Brillouin, 43 Bd 11 Novembre 1918, 69622 Villeurbanne, France.
Physical Review Letters
|May 23, 2006
Summary
Doping silicon nanowires with boron or phosphorus causes impurities to segregate at the surface, reducing conductivity. Passivation further neutralizes dopants at surface defects, impacting carrier density and differing between p- and n-type doping.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Silicon nanowires (SiNWs) are crucial for nanoelectronic devices.
- Doping is essential for tuning SiNW electronic properties.
- Surface effects significantly influence SiNW behavior.
Purpose of the Study:
- Investigate the impact of boron and phosphorus doping on SiNW properties.
- Analyze the role of surface segregation and passivation.
- Understand the mechanisms affecting carrier density and transport.
Main Methods:
- Utilized ab initio simulations for comprehensive analysis.
- Examined structural, electronic, and transport properties.
- Modeled both unpassivated and passivated nanowire surfaces.
Main Results:
- Impurities (boron, phosphorus) segregate to the surface of unpassivated SiNWs, decreasing conductance.
- Passivation leads to dopant trapping at surface defects, neutralizing them and reducing carrier density.
- Observed distinct differences in behavior between p-type (boron) and n-type (phosphorus) doping.
Conclusions:
- Surface segregation and passivation critically affect dopant effectiveness in SiNWs.
- Results provide a theoretical basis for observed experimental phenomena in doped SiNWs.
- Understanding these effects is key for designing reliable SiNW-based electronics.