| dc.description.abstract | Thermoelectric materials have garnered significant attention due to their ability to efficiently convert heat into electricity, making them highly promising for waste heat recovery and sustainable energy applications. Among them, thin-film thermoelectrics have emerged as a key focus area, owing to their enhanced energy conversion efficiency, adaptability for miniaturized and flexible devices, and compatibility with advanced technologies such as IoT devices, wearable electronics, and waste heat recovery systems. Germanium Telluride (GeTe) - based thermoelectric materials stand out due to their high performance, attributed to favorable electronic properties, tunable carrier concentration, structural robustness, and the potential for phase stabilization. As a lead-free thermoelectric material, GeTe has been extensively studied in its rhombohedral and cubic phases. However, its structural phase transition at approximately 700 K, associated with differences in thermal expansion coefficients, poses challenges for broader practical applications. Stabilizing GeTe in a single phase, particularly the cubic phase, which exhibits superior electronic properties and thermoelectric performance, could significantly enhance its utility. This thesis investigates the synthesis of cubic phase GeTe-based thin films using radio frequency (RF) sputtering followed by post-annealing treatment to achieve the desired cubic phase. To further enhance the thermoelectric properties, indium was introduced as a dopant. Comprehensive experimental and computational studies were conducted to analyze the effects of indium doping on the structural, electronic, and thermoelectric properties of the films. Indium, substituting at the germanium site, increases the density of state effective mass and acts as a scattering center, thereby modulating carrier concentration, enhancing the Seebeck coefficient, and reducing total thermal conductivity. These combined effects led to a remarkable improvement in the thermoelectric performance of the material, resulting in approximately a 4-fold enhancement in the dimensionless figure-of-merit (zT) at around 575 K. Moreover an enhancement of ~3-fold in the average zT within the working temperature range of 300 K to 575 K suggest the potential of indium-doped cubic GeSbTe thin films as a promising candidate for high-performance near room temperature, paving the way for further advancements in sustainable energy technologies. | en_US |