Pulsed Laser Ablation of Tin Oxide Nanoparticles in Liquid for Optoelectronic Devices

Abstract

Laser ablation of tin oxide (SnO2) nanoparticles (NPs) was carried out by irradiation of tin target in methanol and aqueous NaCl solutions with nanosecond laser pulses. X-ray diffraction (XRD) studies show that the synthesized nanoparticles are polycrystalline tin oxide with tetragonal phase. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used for characterization of the shape, particle size and particle distribution of tin oxide nanoparticles. SEM results reveal that the synthesized NPs have spherical shape and the presence of agglomerated NPs was observed. TEM investigation confirms that the average particle size of SnO2 synthesized in methanol was 40 nm and in NaCl solution was around 25 nm. The optical energy gap of SnO2 NPs prepared in methanol and NaCl solutions were 3.8 eV and 3.95 eV, respectively. Energy dispersive X-ray (EDX) confirms the formation of SnO2 NPs. The parameters of n-SnO2NPs/p-Si heterojunction photodetectors, namely, dark and illuminated current-voltage characteristics, photovoltaic properties, spectral responsivity and specific detectivity were measured. The responsivity of the photodetector prepared in NaCl solution was 0.53A/W at 410 nm, while the responsivity of photodetector prepared in methanol was 0.43A/W at 410 nm.