Piezo-mechanical impedance of nanosized CdS single crystal

Abstract

The design of a piezo-mechanical device based on nanosized CdS single crystal is a challenging task for demonstration of both the technological capabilities of crystal growth control in order to form simple sensor device topologies and the integrated usage of unique material properties with bottom-up approach. Analysis of luminescence spectra of CdS nanocrystals grown from the gas phase at the temperature 400 °C in the quasi-closed volume revealed that doping takes place with tin, as a component of ITO conductive film, simultaneously with doping with gold or silver from catalyze droplets. Piezo-mechanical longitudinal vibrations along the main symmetry axis of wurtzite-type single crystal have been presented in the continuous medium approximation based on experimental values of the nanocrystal piezo-module. Theoretical analysis of the frequency dependence of resonance oscillations for the nanosized beam-type piezo-mechanical resonators based on the CdS nanocrystal enabled to ascertain the equivalent RLC two-pole and values of the equivalent elements L and C prognosticated: there are high values of L-tens and hundreds of henry and very small values of the series capacitance of the order of femto-and attofarads. Below the resonance, the impedance of the crystal reaches gigaohms and has an inductive character.