Detection of carcinogenic heavy metals using ZnO nanoribbons (ZnONRs): Ab-initio analysis

Abstract

The present work investigates the behaviour of ZnO nanoribbons (ZnONRs) for the detection of carcinogenic heavy metals. Density functional theory along with non-equilibrium Green’s function are used to analyse the ZnO nanoribbons sensing behaviour towards the heavy metal atoms. The heavy metal atoms are passivated at the edges of the ZnO nanoribbons and the change in the structural, electronic, and transport properties are examined for the detection of such heavy metals. Heavy metal passivation at O-rich edge changes the electronic bandgap while the passivation at Zn-rich edge changes the structure behaviour from semiconducting to metallic. The electronic transport results reveal the current magnitude is enhanced upon the heavy metal atom passivation. The current starts conducting after a certain bias voltage irrespective of the device configuration due to semiconducting electrodes . Transmission eigenstates report the electron transport in the passivated devices is mainly from the opposite edge. Zn-rich edge passivated devices have higher magnitudes of current as more carriers are flowing through the O-rich edge due to higher electronegativity of oxygen. From the sensitivity calculations, the Zn-rich passivated devices are reported to exhibit higher sensitivity towards the heavy metal atoms. The obtained results define the efficiency of the ZnONRs towards the design of heavy metal sensors. • Carcinogenic heavy metal atoms detection using ZnO nanoribbons (ZnONRs) is presented. • O-rich edge passivation changes the electronic bandgap. • Zn-rich edge passivation changes the structure from semiconducting to metallic. • Zn-rich edge passivated devices have higher magnitudes of current. • Zn-rich edge passivated devices have higher sensitivity towards the heavy metal atoms.