Nanoelectronic Biosensors and Nanoimprinted Hybrid Perovskite Optoelectronic Devices

Over the past decades, the rapid development of semiconductor technology has triggered a boom in many science and technology fields and brought enormous change to our daily life. Recently, the emergence of nanomaterials, advancement of nanofabrication techniques, and continuous demand of transistor down-scaling have populated research with nanoscale features. With the spirit of application-driven research, my doctoral study has been devoted to enhancing the potential of nanoscale semiconductor devices in electronics, biomedical and optoelectronic applications. In this dissertation, nanoscale field-effect transistors with both quasi one-dimensional structure using Si nanowire and two-dimensional structure using MoS2 are investigated for biosensing, aiming at high-sensitivity, high-stability and high-reliability. The Si nanowire transistors were fabricated using photolithography and electron-beam lithography. The effect of electrical bias with alternating current at both source/drain and gate on sensing sensitivity and stability were studied. The few-layer MoS2 transistors were fabricated using photolithographic patterning, and different gate dielectric structures were investigated for sensing sensitivity and stability. In the next portion of the dissertation, nanoscale organic-inorganic hybrid perovskites, patterned by nanoimprint lithography for the first time, were investigated for optoelectronics, aiming at low-cost and high- efficiency. The physical properties of nanoimprinted perovskite thin-film and the sensitivity of asfabricated photodetectors were investigated. Perovskite nanostructures were further studied for emission enhancement via photonic crystal cavity resonance both numerically and experimentally. This research also extends to investigation of bio-inspired nanoimprint, which utilized pre-existing functional nanostructure from biological surface, for application on optoelectronics.