Abstract
Glancing angle deposition technique was used to grow as-deposited SnO2 and also Gallium doped SnO2 (Ga: SnO2) Nanowire (NW) arrays over Si substrate. The relative amount of Ga dopants was varied from 5% to 20% and tested for various structural and optical characteristics. A blue shift in bandgap and enhanced photo absorption was observed for Ga: SnO2 NWs as compared to the as-deposited SnO2 NWs. Photoluminescence study indicates the suppression of emission due to modification in defects after Ga doping with the least emission in case of 5% Ga: SnO2 NWs which was also supported by the X-ray photoelectron spectroscopy results. Photodetectors (PD) were fabricated using all samples and among them the based-on Au/5% Ga: SnO2 NW/Si device exhibited the lowest dark current (~2.67 nA) along with a maximum photoresponse of ~27. Furthermore, a superior transient response with a rise time and fall time of 1.3 ms and 2 ms respectively was observed for 5% Ga: SnO2 NWs PDs. Thus, large e-h pair generation and reduced defect states in case of 5% Ga: SnO2 NWs sample signifies that gallium doping level of 5% in SnO2 is the optimum concentration for enhanced optoelectronic applications.
NSTL
Elsevier