structural, electrical and optical properties of sno2: b transparent semiconducting thin films

Boron (b) is considered as an important impurity in semiconductor physics and optoelectronic devices, especially to produce p-type silicon (p-si). in this paper, we investigate the effect of boron doping on the structural, electrical, optical, and photo-sensitivity properties of tin oxide (sno2) semiconductor thin films. boron doped tin oxide (sno2: b) thin films were deposited on glass substrates at ts=500 ͦc for different atomic concentration of x=[b/sn] = 0, 0.02, 0.04, 0.08, 0.10, 0.20, 0.30, and 0.50 by spray pyrolysis technique. the results of x-ray diffraction (xrd) analysis show the tetragonal rutile sno2 structure with orientation along the (211) plane. the films have polycrystalline structure with granular and island-like grains morphology by field-emission electron microscope (fe-sem). the sno2:b films have shown n-type conductivity and decreasing - increasing behavior of electrical resistivity with b-doping for x ≤ 0.04 and x> 0.04, respectively. also, carrier concentrations were obtained in the order of 1018-1020 cm-3. average optical transmittance of sno2:b thin films changed in the range of 65% to 87% in the visible region and sno2:b (x=0.08) sample has highest transmittance. the optical gap of films was obtained in the range of 3.47-3.87 ev. from the photoconductive results, the x=0.50 film has exhibited the most optical sensitivity under light radiation.