Zn vacancy induced green luminescence on non-polar surfaces in ZnO nanostructures

Low Temperature Annealed Zinc Oxide Nanostructured Thin Film-Based Transducers: Characterization for Sensing Applications

The performance of sensing surfaces highly relies on nanostructures to enhance their sensitivity and specificity. Herein, nanostructured zinc oxide (ZnO) thin films of various thicknesses were coated on glass and p-type silicon substrates using a sol-gel spin-coating technique. The deposited films were characterized for morphological, structural, and optoelectronic properties by high-resolution measurements. X-ray diffraction analyses revealed that the deposited films have a c-axis orientation and display peaks that refer to ZnO, which exhibits a hexagonal structure with a preferable plane orientation (002). The thicknesses of ZnO thin films prepared using 1, 3, 5, and 7 cycles were measured to be 40, 60, 100, and 200 nm, respectively. The increment in grain size of the thin film from 21 to 52 nm was noticed, when its thickness was increased from 40 to 200 nm, whereas the band gap value decreased from 3.282 to 3.268 eV. Band gap value of ZnO thin film with thickness of 200 nm at pH ranging from 2 to 10 reduces from 3.263eV to 3.200 eV. Furthermore, to evaluate the transducing capacity of the ZnO nanostructure, the refractive index, optoelectric constant, and bulk modulus were analyzed and correlated. The highest thickness (200 nm) of ZnO film, embedded with an interdigitated electrode that behaves as a pH-sensing electrode, could sense pH variations in the range of 2-10. It showed a highly sensitive response of 444 μAmM^-1cm^-2 with a linear regression of R² =0.9304. The measured sensitivity of the developed device for pH per unit is 3.72μA/pH.

Role of Zn-interstitial defect states on d0 ferromagnetism of mechanically milled ZnO nanoparticles

An impurity defect level formed by interstitial zinc at the surfaces of undoped ZnO nanoparticles plays a crucial role for d0 ferromagnetism.

Catalytic potential of highly defective (211) surfaces of zinc blende ZnO

The special structure of the zinc blende ZnO surface (211) results in its polarity, high energy and stabilized surface defects.

Reagent concentration dependent variations in the stability and photoluminescence of silica-coated ZnO nanorods

ZnO nanorods produced hydrothermally, using different precursor concentrations, show strikingly different morphologies and photoluminescence properties after encapsulation in silica. These differences are traced to differences in the nanorod growth chemistry.

A successive photocurrent transient study to probe the sub-band gap electron and hole traps in ZnO nanorods

Probing of the sub-band gap electron and hole traps in ZnO nanorods has been carried out using a simple technique of successive photocurrent transients.