____________________________________________________________________

_____________________________________________________________________

Tin Dioxide

Crystal: SnO₂

Structure: Rutile

_____________________________________________________________________

Mechanical and structural properties:

Cohesive energy:	eV
Lattice parameter:	a= 4.737 Å
	c= 3.186 Å
	c/a = 0.673
	u = 0.307
	O-O distance: 4.6646 Ang.
	O-Sn distance: 3.7662 Ang
Density:	g/cm³

Stiffness constants: in 10¹¹ dynes/cm², at room temperature

c₁₁: See Ref. 1

c₁₂:

c₄₄:

Compressibility (in 10¹¹ dynes/cm²):

Poisson ratio:

Debye temperature: K

Melting temperature: ° C

Neel temperature: K

Phonon spectrum discussed by:

S. Peercy, B. Morosin, Pressure and temperature dependence of the Raman-active phonons in SnO2, Phys. Rev. B7, 2779 (1973)

Transverse optic phonon T0 (k=0): cm^-1

Longitude optic phonon L0 (k=0): cm^-1

Gruneissen constant:

Ratio e*/e:

Photoelastic constants:

p₁₁:

p₁₂:

p₄₄:

Electronic properties:

Electronic structure:

Sn [1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6][4d10 5s2 5p2] (valence)

Band gap:

direct: E^ = 3.57 eV., E// = 3.93 eV.

indirect: ~ 2.7 eV.

Direct extrema at G (conduction & valence) BUT valence band has maximum at R (essentially [011] point if c axis =2)

Valence band maximum: [011]

Gap: eV.

First exciton: eV.

Direct forbidden gap materials including SnO2 data:

Y.I. Ravich, B.A. Efimova, V.I. Tamarchenko, Scattering of current carriers and transport phenomena in lead chalcogenides. I. Theory, Phys. Stat. Sol. 43, 11 (1977)

Band structure discussed by:

F.J. Arlinghaus, Energy bands in Stannic Oxide (SnO2), J. Phys. Chem. Sol. 35, 931 (1974)

UV data:

J.A. Marley, N.F. Bouelli; The UV absorption edge of Stannic Oxide (SnO2), J. Phys. Chem. Soc. 25, 1465 (1964)

See also: W. Spence, The UV absorption edge of TiO thin films, J. Appl. Phys. 38, 3767 (1967)

Static dielectric constant: //=9.86 and ^ =14.0 (Ref.2)

Optic dielectric constant: //=4.175 and ^ =3.785

SnO2 thermally-modulated optic transmission:

- Possible LO phonons: 34, 46, 95 meV

- cite: K¥ =3.785, Ko=13.5, m*(dens.st.)=0.275 mo, a ~0.9

- E//c direct allowed transmission: ~4.0 eV.

S.T. Pantelides, D.J. Mickish and A.B. Kunz; Electronic structure and properties of magnesium oxide, Phys.Rev. B10, 5213 (1974)

Electron mobility:

Hole mobility:

Conductivity width: ~3.2 eV.

Polaron coupling constant: a = ( for m*=1 )

Effective mass: m//=0.234, m^ =0.299, m(dens.of states)=0.275 (Ref.3)

Electron affinity: ( in eV., from bottom of conduction band under vacuum)

Spin-orbit coupling: ( valence band)

Cation polarisation: Å^-3Anion polarisation: Å^-3

_____________________________________________________________________

Other information:

Raman active phonon + compression along a, c axes: see Phonon spectrum.

See also supplementary information on SnO₂, below.

_____________________________________________________________________

References:

1. Chang, J. Geophys. Res. 80, 2595 (1975)

2. D.M. Roessler, W.A. Albers, IR reflectance of single crystal tetragonal GeO2, J. Phys .Chem. Soc. 33, 393 (1972)

3. K.J. Button, C.G. Fonstad, W. Debrodt, Determination of the electron masses in stannic oxide by submillimeter cyclotron resonance, Phys. Rev. B4, 4539 (1971)

_____________________________________________________________________

Supplementary information on SnO₂:

Mossbauer lattice temperature of tetragonal (P4/nmm) SnO.

R.H.Herbert ,Phys. Rev. B27, 4013 (1983)

The lattice-dynamical properties of tetragonal (black) SnO (with space-group symmetry P4/nmm) have been examined over the temperature range 78 <T<3000K. by variable-temperature 119Sn Mossbauer-effect measurements. The lattice temperature calculated from the temperature dependence of the recoil-free fraction (assuming the atomic mass) is 229K. Using the effective vibrating mass calculated from the temperature dependence of the isomer shift (Meff=16 g/mol.) leads to a lattice temperature of 193K.The quadrupole-coupling hyperfine parameter is only weakly temperature dependent over the above temperature range, and there is no evidence of a vibrational anisotropy parallel and perpendicular to the fourfold rotational axis trough the metal atom. The recoil-free fraction at 295K is 0.35±0.02.

Exciton luminescence emitted by tin dioxide crystals.

V.F. Agekyan, Yu.A. Stepanov , Sov. Phys. Sol. St. (1991)

The exciton photoluminescence spectra of tin dioxide single crystals were investigated under interband pulsed excitation conditions and the dependencies of the intensities of the exciton lines (due to free excitons and those bound to oxygen vacancy clusters) were determined. The spectra of samples with low and high oxygen vacancy concentrations were used to interpret the structure of the phonon replica spectrum, governed primarily by the LO phonons. Under the adopted experimental conditions the effective temperature of excitons was much higher than the crystal lattice temperature.

_____________________________________________________________________