Special Features of the Electrical Conductivity in Doped {alpha}-Si:H Films with Silicon Nanocrystals
- Institute of Semiconductor Physics, Siberian Division, Russian Academy of Sciences, pr. Akademika Lavrent'eva 13, Novosibirsk, 630090 (Russian Federation)
The electrical properties of undoped and phosphorus-doped {alpha}-Si:H films with Si nanocrystals are studied. The silicon nanocrystals are formed by a solid-solid phase transition resulting from the nanosecond effect of a XeCl excimer laser on an amorphous film. The formation of the nanocrystals in the undoped films is accompanied by an increase in the electrical conductivity by two to three orders of magnitude and a simultaneous decrease in the effective activation energy of the conductivity from 0.7 to 0.14 eV. The nanocrystal sizes range from 2 to 10 nm for various laser treatment modes and are determined from Raman scattering data and high-resolution electron microscopy. The temperature dependence of the Fermi level is obtained by calculating the energies of the localized states of electrons and holes in the nanocrystals. It is shown that, as the temperature decreases, the Fermi level tends to the energy of the states in the Si nanocrystals for a wide concentration range of the dopant. The Fermi level's location close to the states in the nanocrystals is a consequence of the fact that these states are multicharged. It is found that phosphorus effectively transforms into an electrically active state during laser treatment of the doped amorphous Si films, which is an important consideration in the fabrication of shallow p-n junctions and contacts for amorphous Si films.
- OSTI ID:
- 20658160
- Journal Information:
- Semiconductors, Vol. 39, Issue 4; Other Information: Translated from Fizika i Tekhnika Poluprovodnikov, ISSN 0015-3222, 39, 472-478 (No. 4, 2005); DOI: 10.1134/1.1900260; (c) 2005 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACTIVATION ENERGY
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRON MICROSCOPY
ELECTRONS
EXCIMER LASERS
FERMI LEVEL
HOLES
HYDROGEN
MILLI EV RANGE
NANOSTRUCTURES
P-N JUNCTIONS
PHASE TRANSFORMATIONS
PHOSPHORUS
RAMAN EFFECT
RAMAN SPECTRA
SEMICONDUCTOR MATERIALS
SILICON
TEMPERATURE DEPENDENCE
THIN FILMS