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Structural properties of SnO 2 nanowires and the effect of donor like defects on its charge distribution
Author(s) -
Zervos M.,
Othonos A.,
Tsokkou D.,
Kioseoglou J.,
Pavlidou E.,
Komninou P.
Publication year - 2013
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201200403
Subject(s) - nanowire , materials science , charge density , band gap , density of states , absorption (acoustics) , spectroscopy , fermi level , band bending , molecular physics , absorption spectroscopy , tetragonal crystal system , absorption edge , condensed matter physics , chemistry , optics , nanotechnology , crystal structure , electron , crystallography , optoelectronics , physics , quantum mechanics , composite material
Tin oxide (SnO 2 ) nanowires (NWs) with diameters of 50 nm, lengths up to 100 µm and a tetragonal rutile crystal structure have been grown by low pressure reactive vapour transport on 1 nm Au/Si(001). The free carrier density of the SnO 2 NWs measured by THz absorption spectroscopy was found to be n = (3.3 ± 0.4) × 10 16 cm −3 . Based on this we have determined the one‐dimensional (1D) sub‐band energies, overall charge distribution and band bending via the self‐consistent solution of the Poisson–Schrödinger equations in cylindrical coordinates and in the effective mass approximation. We find that a high density of 10 18 –10 19 cm −3 donor‐like defect related states is required to obtain a line density of 0.7 × 10 9 close to the measured value by taking the Fermi level to be situated ≈0.7 eV below the conduction band edge at the surface which gives a surface depletion shell thickness of 15 nm. We discuss the origin of the donor‐like states that are energetically located in the upper half of the energy band gap as determined by ultrafast, time‐resolved absorption–transmission spectroscopy.