Structural properties of SnO sub(2) nanowires and the effect of donor like defects on its charge distribution

• Published in: Physica status solidi. A, Applications and materials science Vol. 210; no. 1; pp. 226 - 229
• Main Authors: Zervos, M, Othonos, A, Tsokkou, D, Kioseoglou, J, Pavlidou, E, Komninou, P
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• Subjects: Charge distribution; Crystal defects; Density; Mathematical analysis; Nanowires; Surface chemistry; Tin dioxide; Tin oxides
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201200403

Tin oxide (SnO sub(2)) nanowires (NWs) with diameters of 50nm, lengths up to 100 mu m and a tetragonal rutile crystal structure have been grown by low pressure reactive vapour transport on 1nm Au/Si(001). The free carrier density of the SnO sub(2) NWs measured by THz absorption spectroscopy was found to be n=(3.3 plus or minus 0.4)10 super(16)cm super(-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-Schrodinger equations in cylindrical coordinates and in the effective mass approximation. We find that a high density of 10 super(18)-10 super(19)cm super(-3) donor-like defect related states is required to obtain a line density of 0.710 super(9) close to the measured value by taking the Fermi level to be situated approximately 0.7eV below the conduction band edge at the surface which gives a surface depletion shell thickness of 15nm. 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.