Growth And Characterızatıon Of CdTe Based Crystals By Vertical Gradient Freezing Method

Date

2025-1

Author

Gülen, Elif

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

79
views

0
downloads

Cite This

This thesis examines the crystal growth and characterization of Cadmium Telluride (CdTe) and its derivatives to enhance materials for radiation detection. Cadmium Zinc Telluride (CZT) is the leading choice for X-ray and gamma-ray detectors due to its high atomic number, optimal bandgap, and room-temperature operation. However, challenges such as compositional inhomogeneity and defect density limit its application. This study investigates incorporating Zinc (Zn), Manganese (Mn), and Selenium (Se) into CdTe matrices, forming quaternary compounds, Cadmium Zinc Telluride Selenide (CZTS) and Cadmium Manganese Telluride Selenide (CMTS). Selenium improves stoichiometric homogeneity and reduces defects, while Manganese enhances stoichiometric uniformity, and Zinc enhances bandgap properties. Crystals were grown using the multi-zone Vertical Gradient Freezing (VGF) method at the Middle East Technical University Crystal Growth Laboratory (METU-CGL). The grown crystals were characterized using X-ray Diffraction (XRD), Photoluminescence (PL), Infrared (IR) Microscopy, Energy Dispersive X-ray Spectroscopy (EDX), and Current-Voltage (I-V) measurements to evaluate their structural, optical, and electronic properties. These techniques provided insights into stoichiometric uniformity, defect density, bandgap variations, and charge transport properties. Among the grown samples, CZTS with 2% Se exhibited superior performance with high resistivity, enhanced electron mobility-lifetime product, and stable contact behavior, marking it a promising material for detector-grade applications. In contrast, CZTS with 3% Se displayed more variability in properties along the growth direction. MTMn and MTMnSe samples showed limited performance. The incorporation of Zn, Se, and Mn into the CdTe matrix enhances material quality and performance, paving the way for advancements in medical imaging, security screening, and industrial applications.

Subject Keywords

CdTe, CdZnTe, CdZnTeSe, CdMnTe, CdMnTeSe, VGF

URI

https://hdl.handle.net/11511/113761

Collections

Graduate School of Natural and Applied Sciences, Thesis