Physics Colloquium: Controlled Doping of Semiconductor Nanowires
Prof. Yossi Rosenwaks
Dept. of Physical Electronics, Tel-Aviv Universit
Controlled dopant profiles and abrupt electrical junctions are essential for the operation of current and future semiconductor devices, and represent one of the major challenges that the semiconductor industry and scientific community is facing.
We use quantitative Kelvin probe force microscopy (KPFM) and nano-probe scanning Auger spectroscopy to measure both the longitudinal and radial dopant distribution in vapor-liquid-solid (VLS) grown doped Si nanowires . We find that both VLS and vapor-solid (VS) doping mechanisms result in very inhomogeneous doping distribution. These results are compared to measurements conducted on monolayer doped NWs . This process makes an advantage of the selectivity and controllability of chemical monolayer formation to produce tailor-made dopant profiles.
In the last part of the talk I will present an electrostatically formed nanowire (EFN) which is a nanowire-like charge conducting channel that is not physically fabricated, but rather, electrostatically formed post-fabrication . The fabrication and comparison with bottom-up grown nanowires will be discussed.
 I. Amit, Uri Givan, Justin G. Connell, Dennis F. Paul, John S. Hammond, Lincoln J. Lauhon and Y. Rosenwaks, Nanoletters, dx.doi.org/10.1021/nl4007062 .
 O. Hazut, A. Agarwala, I. Amit, T. Subramani, S. Zaidiner, Y. Rosenwaks, and R. Yerushalmi, ACS Nano 6, 10311-18 (2012).
 G. Shalev, G. Landman, I. Amit, Y. Rosenwaks, and I. Levy, Asia Nature Materials, 3, (2013).
* This work is in collaboration with I. Amit, E. Koren, E. Halpern, G. Shalev and A. Henning Tel-Aviv University, U. Givan, E. Hemesath and L.J. Lauhon, Northwestern University, Illinois, U.S.A, and O. Hazut, and R. Yerushalmi, Hebrew University, Jerusalem, Israel.