Growth ambient dependence of defects, structural disorder and photoluminescence in SnO2 films deposited by reactive magnetron sputtering

The present paper deals with the study of photoluminescence (PL) and the other physical properties (structural, electrical and optical) of SnO2 thin films with controlled disorder and intrinsic defects induced during the reactive magnetron sputtering by changing oxygen flow rate from 12 to 16 sccm. The changes in unit cell volume, near band-edge optical transparency and width of Urbach tail in the films are correlated with the structural disorder and presence of intrinsic defects induced by growth under different oxygen partial pressures. The increased intensity of the PL near UV emission and decrease in the intensity of visible emission peaks with increase in oxygen flow rate is linked with the decrease in oxygen vacancies and tin interstitials in the films. With increasing oxygen content, whereas the electrical resistivity of the films minimizes to a value of 4.3 × 10−2 ohm cm at 14 sccm, the mobility of the films increases to a saturation value 15 cm2 V−1 s−1. The donor-defect concentration linked carrier density is observed to decrease monotonically from 2 × 1019 to 0.6 × 1019 cm−3.