Modification of electrical and piezoelectric properties of ZnO nanorods based on arsenic incorporation via low temperature spin-on-dopant method

We report on the control of the electrical and the piezoelectric properties of ZnO nanorods (NRs) by incorporation of arsenic (As) elements via a low-temperature processed spin-on-dopant (SOD) method. The structural investigations for the SOD-treated ZnO NRs at different temperatures show a negligible change in morphology at temperatures up to 550 °C and melting of the ZnO NRs at 600 °C. Low-temperature photoluminescence (PL) spectra show gradual development of acceptor-related emission peaks with increasing SOD treatment temperature from 450 to 550 °C, which indicates the successful incorporation of As atoms into the ZnO NRs. An As_Zn-2V_Zn shallow acceptor model is suggested by considering the formation energy of the interstitial point-defect complex for the modification of the electrical properties of ZnO NRs. A ZnO NR/n-Si heterojunction showed better rectifying behavior with increasing SOD treatment temperature, indicating better incorporation of As-dopants at higher SOD treatment temperatures. A piezoelectric nanogenerator was fabricated as a device application of the electrical-property-modified ZnO NRs. The nanogenerator showed enhanced piezoelectric output potential after doping due to the elimination of the screening effect by free charge carriers in the ZnO NRs.