Elucidation of the unsymmetrical effect on the piezoelectric and semiconducting
properties of Cd-doped 1D-ZnO nanorods†
Yuvasree Purusothaman,a Nagamalleswara Rao Alluri,b Arunkumar Chandrasekhara and Sang-Jae Kim*a
Herein, we report the unsymmetric effect on the functional (piezoelectric and semiconducting)
properties of cadmium-doped 1D-ZnO nanorods (NRs), which have a higher ionic radius (0.97 Å). The
growth of Cd-ZnO NRs, which have a hexagonal wurtzite structure without any secondary CdO phases,
along the c-axis was confirmed by the XRD patterns, and oxidation states observed from XPS analyses
verified the diffusion of Cd2+ into ZnO NRs. A one-fold reduction in the piezoelectric properties was
determined by the fabrication of a nanogenerator, and enhancement in the semiconducting properties
was studied using an Ag/Cd-ZnO NRs/Ag device with various wt% of Cd doped into the ZnO NRs lattice.
Cd-ZnO NRs improve the photogenerated charge carriers (Iph B 330 mA) compared to pure ZnO NRs
(Iph B 213 mA), obtained at a bias voltage of 10 V, a wavelength of 365 nm and a light intensity of 8 mW cm2.
The Cd-ZnO NRs (1 wt%) based sensor shows good photoresponse with a detectivity (D*) limit of 1 1011 cm
H1/2 W1 compared to that of pure ZnO NRs (D* = 5.4 1010 cm H1/2 W1). We also demonstrate a selfpowered
UV sensor (SPUV-S) connected parallel to the ZnO NRs based nanogenerator as an independent
power source to drive the Cd-ZnO NRs UV sensor. The low-temperature hydrothermal synthesis of Cd-ZnO
NRs is simple, cost-effective, and scalable for industrial applications.