Growth temperature-dependent morphological, optical, and electrical study of SnO2 thin film by atomic layer deposition

Low temperature, high quality SnO2 thin film successfully deposited by the atomic layer deposition (ALD) method using tetrakis (dimethylamino)Sn (TDMASn) and O3-plasma. The influence of various growth temperatures having ranges between 115 °C to 250 °C on the film growth rate, morphology, composition, optical and electrical properties have been elucidated, and remarkable differences were noticed for possible electron transport layer (ETL). It was worth observing that the film growth rate steeply increased from 0.046 nm/cycle to 0.192 nm/cycle between the growth temperature range 115–250 °C because of the rapid dissociation of TDMASn precursor relative to temperature increase. The optical transmittances of films showed 81%–97% at the visible region for all growth temperatures; however, the optical bandgap energy of the SnO2 film was decreased from 3.4 eV to 3.1 eV while increasing deposition temperature. During lower deposition temperature of 115 °C, the film obtained high resistivity (7.3 × 102 Ω cm), while at a high growth temperature of 200 °C almost impurity-free low resistivity (8.9 × 10−4 Ω cm) film can be achieved apart from high carrier concentration (1.4 × 1021 cm−3) and 12.5 cm2 V−1s−1 mobility.