Metodologie innovative di sintesi e studio della struttura elettronica di dicalcogenuri di metalli di transizione "quasi-2D": il caso del MoS2

Transition metal dichalcogenides (TMDCs) are a class of recently emerged semiconductor materials, which has attracted enormous interests due to their intriguing physical, chemical and electrical properties. They show a typical layered structure, thus being promising 2D materials with semiconducting properties for electronics. The laboratory scale TMDC-based electronic devices like transistor, sensors, memristor etc. have been demonstrated, especially using few or single layer material and the outcome sparked hopes to obtain highly efficient electronic devices beyond Si-CMOS technology. However, the path through realization of electronic devices based on two dimensional TMDCs is suffering from many challenges which should be overcome. Controlling the surface electronic properties, role of defects and scalable synthesis of few/single layer TMDCs with large dimensions are some of the important issues still needed to be more investigated. In this thesis, the influence of Sulfur defects on surface electronic energy levels, specially the work function (WF) has been investigated. Moreover, the possibility to recover the pristine surface electronic properties via thiol molecule interaction with surface defective sites is studied. In the last part, a novel physical vacuum deposition technique, so called Ionized Jet Deposition (IJD) has been used for the first time to synthesize MoS2 thin film. The deposited material shows intriguing optical and electronic properties. IJD found to be a promising candidate for scalable synthesis of TMDCs materials applicable in electronic and optoelectronic devices