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Facile synthesis and electrical characteristics of n-SnO2/p-NiO nanowire heterojunctions

In the current work, we report a facile synthesis of n-SnO2/p-NiO nanowire heterojunctions by a drop-coating approach. The pure SnO2 and NiO nanowires (NWs) were grown by chemical vapor deposition (CVD) and hydrothermal methods, respectively. Morphology, composition and crystal structures of the NWs and heterojunctions were investigated by means of field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. | Communications in Physics, Vol. 29, No. 1 (2019), pp. 71-79 DOI:10.15625/0868-3166/29/1/13510 FACILE SYNTHESIS AND ELECTRICAL CHARACTERISTICS OF n-SnO2 /p-NiO NANOWIRE HETEROJUNCTIONS DANG THI THANH LE AND CHU MANH HUNG † International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1 Dai Co Viet, Hanoi, Vietnam † E-mail: mhchu@itims.edu.vn/hung.chumanh@hust.edu.vn Received 27 December 2018 Accepted for publication 18 February 2019 Published 8 March 2019 Abstract. In the current work, we report a facile synthesis of n-SnO2 /p-NiO nanowire heterojunctions by a drop-coating approach. The pure SnO2 and NiO nanowires (NWs) were grown by chemical vapor deposition (CVD) and hydrothermal methods, respectively. Morphology, composition and crystal structures of the NWs and heterojunctions were investigated by means of field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The data showed that SnO2 NWs were grown with their average diameter of 200 nm and length of about 15 µm. The NiO NWs were also synthesized with a shorter average length and smaller average diameter compared to those of the SnO2 NWs. The EDS results indicated no impurity present in both SnO2 and NiO NWs. The XRD patterns pointed out the tetragonal rutile and cubic structures of SnO2 and NiO, respectively. Interestingly, electrical properties of the NWs and heterojunctions were studied through the Keithley 2602A sourcemeterbased I −V characterizations. The results confirm the nature of the metal semiconducting oxides. The formation of the n-SnO2 /p-NiO heterojunctions was certified through the rectifying behavior of the I-V curves with the rectification ratio of about 5 at ± 3V and 350˚C. The potential energy barrier between the NWs was also estimated to be about 1.16 eV. The band energy structure was also proposed to get insight into characteristics of the n-SnO2 /p-NiO .