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conferenceseries.com
October 20-22, 2016 Rome, Italy
11th International Conference and Expo on
Nanoscience and Molecular Nanotechnology
Volume 7, Issue 5 (Suppl) J Nanomed Nanotechnol 2016
ISSN: 2157-7439 JNMNT an open access journal NanoScience 2016
October 20-22, 2016
Geometry induced doping in thin Si nano-grating layers
M Mebonia1,3 , A Tavkhelidze 1, L Jangidze2, G Skhiladze2, D Ursutiu4, C Samoila4, Z Taliashvili2 and L Nadaraia5
1Ilia State University, Georgia
2Institute of Micro and Nano Electronics, Georgia
3Peter Grünberg Institute, Germany
4Transilvania University of Brasov, Romania
5Georgian Technical University, Georgia
Recently, new quantum features have been studied in the area of nanostructured layers. Nano-grating on the surface of the
thin layer imposes additional boundary conditions on the electron wave function and induces G-doping or geometry doping.
G-doping is equivalent to donor doping from the point of view of the increase in electron concentration n. However, there are
no ionized impurities. This preserves charge carrier scattering to the intrinsic semiconductor level and increases carrier mobility
with respect to the conventionally doped layer. We fabricated Si nano-grating layers and measured their electrical characteristics to
monitor geometry induced doping (G-doping). Grating was fabricated using laser interference lithography (375 nm laser) followed
by reactive ion etching of Si. Next, large square island (0.3 x 0.3 mm) was shaped in the device layer and 4 Si\Ti\Ag ohmic contacts
were formed to measure electrical characteristics. The I-V characteristics were recorded using both 4 wire and 2 wire methods.
Resistance-temperature (T) dependences (T=4-300 K) were recorded as well. For all 12 samples, nano-grating layers show 2-3 order
of magnitude reduction in resistivity. Resistivity anisotropy was in the range 0.2-1 at 300 K. Obtained geometry induced doping level
corresponds to “Effective Impurity” concentration of 3 x 1018 cm-3. The (T) dependence is in agreement with G-doping theory. It was
observed (data from 12 samples) that nano-grating reduces resistivity of Si layer from 10 Ohm cm (plain layer) to 5 x 10-2-8 x 10-3
Ohm cm. This reduction is in agreement with theoretical prediction of G-doping. Value 10-2 Ohm cm corresponds to “Impurity”
concentration of 3 x 1018 cm-3 (phosphorous in Si). G-doping does not require ionized impurities. This allows high carrier mobility
and temperature independent carrier concentration. Nano-grating fabrication does not require sophisticated technology and can be
used for solar cells and other photovoltaic devices, ultra high frequency electronics and power electronics.
Biography
M Mebonia has completed his Master’s from Ilia State University and started his PhD at the same university collaborated with RWTH Aachen University. Since
2014, he has been working in Research Centre Juelich and Fraunhofer Institute of Laser Technology as a PhD Researcher. From 2013, he has been working in
Scientific and Technological Centre "Nano Structured Materials for Renewable Energy" the School of Engineering in Ilia State University. He has published some
papers in reputed journals.
M Mebonia et al., J Nanomed Nanotechnol 2016, 7:5 (Suppl)