MICROWAVE CIRCUIT ANALYZERS ON A MULTI-PROBE MEASURING LINE. REVIEW OF SIGNAL PROCESSING METHODS, PROBLEMS AND PROSPECTS (REVIEW)

Nanostructured materials, particularly zinc oxide (ZnO), have attracted significant attention due totheir wide range of applications, including piezoelectric devices, gas sensors, and photocatalysis. In particular,ZnO nanorods with their one-dimensional structure possess a high surface area and tunable morphology.This study investigates the effect of various synthesis conditions on the morphology of ZnO nanorods formedby chemical deposition. The impact of zinc oxide precursor concentration and auxiliary substances in theseeding solution, thermal treatment time, seed layer thickness, seed center diameter, and substrate type onthe morphology of ZnO nanorods is examined. It is found that changing the concentration of hexamethylenetetramine(HMTA) has a minor effect on nanorod dimensions, while reducing the seeding solution concentrationresults in decreasing their length from 380±28 nm to 247±41 nm. Increasing the seed layer thicknesspromotes larger nanostructures and leads to an increase in average rod diameter from 86±12 nm to 102±13nm and length from 356±29 nm to 391±46 nm. Reducing the seeding solution concentration decreases seedcenter diameters from 9±1 nm to 7±1 nm; conversely, reducing thermal treatment time increases them due toincomplete thermal decomposition of precursors. Horizontal positioning of substrates suppresses verticalgrowth due to active nucleation in bulk reaction solutions followed by deposition onto substrates; verticalpositioning enhances crystal length instead. The obtained results provide valuable insights for directed synthesisof ZnO nanorods with specified characteristics for various applications