Piezo-phototronic Effect Enhanced UV/Visible Photodetector Based on ZnO/NiO Nanowire Array With Interfacial Strain

【摘要】：The UV/visible detection of ZnO/NiO nanowire arrays is firstly found,that is the low energies photons could be detected which are significantly smaller than the band gap of ZnO(3.3 eV) and NiO(3.7 eV),and ZnO/NiO core/shell nanowire arrays have been successfully fabricated by the two-step solution method via the hydrothermal growth and ion exchanging process.The I-V and I-t test show that the photodetecting wavelength could be broaden to the visible wavelength of 671 nm.The lattice mismatching of interface between the shell NiO and the core ZnO plays an important role on the low energies photoelectric response,which is mainly attributed to the contribution of compressive strain and distortion in parent lattice because of the different ionic radius of Ni and Zn.Furthermore,the spectral response of the device was further enhanced through pizeo-electric effect,which could modulate the potential barrier distance of ZnO/NiO interface.The six orders enhancement of wider spectral responsivity was obtained at four different excitation wavelengths(355 nm,405 nm,532 nm,671 nm).This work provides not only a facile solution processing for the UV/visible photodetectors based on the strain driving,but also strategy for enhancing performance through the piezo-phototronic effect.