It has been 75 years since the invention of the transistor that heralded the modern electronic age. Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) have attracted tremendous interest for high-performance and energy-efficient nanoscale field-effect transistors (FETs). Despite recent advances in down-scaling the gate and channel lengths, the fabrication of sub-25 nm narrow channel of TMDC FETs remained challenging. In my talk, I will demonstrate the fabrication of tungsten disulfide (WS2) nanoribbon down to sub-10 nm width. Nanoribbon FETs exhibit good transistor performance, where the transport parameters are governed by the narrow channel effects. In addition, scalable chemical vapour deposition (CVD)-grown MoS2 and graphene FETs are very promising for future nanodevices, especially for flexible solar cells, memory devices, and neuromorphic computing. I will also show transport properties, memristive switching, and Schottky barrier analysis in CVD-grown MoS2 -graphene heterostructure FET devices. These findings open the door for the fabrication of future-generation nanometer-scale transistors, sensors, and optoelectronic devices based on van der Waals semiconductors.