Fundamental Studies on Confinement Effects in Ionic Conduction and Inversion Layers in 2-D Single Crystal Free Standing Oxide Membranes

摘要

New experimental techniques need to be developed to investigate the physical properties of suspended oxide membranes approaching twodimensionality. Here, we report on our progress to demonstrate a robust lithographic patterning method to fabricate self-supported ultra-thin oxides that undergo sharp structural transitions. Utilizing such self-supported membranes, we have directly observed shift in metal-insulator transition temperature arising from stress relaxation and consistent opening of the hysteresis in a model system vanadium dioxide. Electric double layer transistors are then fabricated with the membranes and compared to thin film devices. The ionic liquid allowed reversible modulation of channel resistance and allowed distinguishing bulk process from the surface effects. The techniques developed here can be widley adapted to studies of new materials in 2D suspended form.