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As an alternative of chemical manipulations, external pressure is a fundamental thermodynamic variable that can dramatically alter the atomic and electronic structure of promising frontier materials, resulting in concomitant changes to their physical properties. In addition, enhancing functionalities or addition of new phenomena of well-known materials by synergy is a realistic rationale to innovate the prospect of futuristic device applications. It resulted the successful fabrication of nanodevices inside a diamond-anvil cell (DAC) to demonstrated the synergy between light and pressure (opto-mechanical), pressure and field-effect (mechano-electrostatic) with unprecedented properties and realistic applications. In this context, photoconductivity serves as a complimentary probe to the regular electrical resistivity and helps to explain the complex interplay among the light generated carriers, native defects, band-structure modification, and structural transition relating the changes in local coordination environment under external stimuli. In my presentation, the tuning effect of the structure and defects on the oxide semiconductors and the novel pressure-induced enhancement of visible light photoconductivity under the simultaneous influence of illumination and hydrostatic pressure will be discussed.
The era of miniaturization also leads to the fabrication of a “single” metal-carbon composite nanowire device inside a DAC to record the pressure-induced dramatic response of the electron conduction process determined by the nanostructure along with its conductive platinum nanograin network in the amorphous carbonaceous matrix. This display of high sensitivity on transport properties over the coupling strength of internal constituents, morphology, structural deformation, and disorder will be discussed in my presentation. Our experiment derives the strong correlation between macroscopic (classical percolation) and quantum (tunneling) phenomena in a single nanowire system, remained unnoticed so far. A unique access to the structural phase progressions were monitored by in-situ transmission electron microscopy to evidence the pressure-induced shape reconstruction of the metallic grains and modifications of their intergrain interactions for successful explanations of the electrical transport behavior. |