Theoretical Study of Hydrostatic Pressure and Temperature Effect on a Multi-Quantum well ZnO/Zn_1-XMg_xO Containing a Staircase Defect for Sensing Application

Abstract

This work describes a theoretical and analytical study of a temperature and pressure sensor based on II-VI semiconductors with a simple multi-quantum wells (MQWs) structure. The proposed sensor operates by detecting changes in the intensity (transmission coefficient) and energy of localized electronic states inside gaps under external perturbations of hydrostatic pressure and temperature. Specifically, the proposed MQWs structure is ZnO/Zn1-XMgXO with 10 cells, each containing two materials that form the wells and barriers, respectively. The structure is perturbed by a staircase defect consisting of three defects of the same material or geomaterial. The Green function method is used to study the transmittance of the structure, with cleavage and coupling operators employed. The objective of the work is to explore a new type of defect for use in sensing applications such as multi-quantum well sensors. Key parameters for evaluating the sensor's performance include full width at half maximum (FWHM), sensor sensitivity (S), quality factor (QF), detection limit (DL), signal-to-noise ratio (SNR), dynamic range (DR), detection accuracy (DA), the figure of merit (MF), and standard deviation. These parameters can be optimized by adjusting structural parameters such as the thickness of the staircase or material concentration. The study found that a geomaterial staircase defect provides higher sensitivity to pressure and temperature changes. Additionally, the step (δx) of the staircase defect influences the sensitivity of the localized states: with increasing steps, δx improves sensitivity to temperature and decreases sensitivity to pressure.