|Abstract or Summary
- Digital printing techniques offer several advantages in manufacturing electronics such as direct writing of materials, reduction of chemical waste, and scalability. In particular, printing can significantly simplify manufacturing processes by directly defining the channel area, the gate, and the source and drain contacts, allowing for lower costs and higher throughput manufacture of Thin Film Transistors (TFTs). Pyrite (FeS₂) and ternary compound iron germanium sulfide (Fe₂GeS₄) are compound semiconductors which consist of earth abundant elements. Both materials are being studied as promising candidates for thin film photovoltaics. In this study, iron sulfide and iron germanium sulfide thin films were fabricated by ink-jet printing for the first time. The films were formed by simply inkjet printing iron and germanium salts followed by air annealing and sulfurization. Thin films were characterized by Ultraviolet-visible spectroscopy, X-ray diffraction, Scanning electron microscopy, Atomic force microscopy and Hall-effect measurements. The characterization results indicate P-type iron sulfide and iron germanium sulfide thin films were successfully fabricated. TFTs were fabricated and characterized using inkjet printed FeS₂ thin films on SiO₂/Mo/Glass substrates. The devices clearly show linear increment of the drain current as a function drain voltage and could be modulated by varying the gate voltage. However, the TFTs seem to show ambipolar behaviors. Better understandings of defects and electrical properties are needed to develop strategies that could improve pyrite-based TFT performance.