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In this work, the dynamical analysis of carrier transportation in a typical piezoelectric device working in the ballistic regime is conducted. Based on the quantum scatting theory, the Poisson and Schrödinger equations are combined for calculating the dynamical transmission coefficient of the metal–piezoelectric ZnO–metal structure subject to sinusoidal and rectangular external stresses. The roles played by the spanning width of induced piezopotential and incident electron energy in affecting transmission probability are further discussed and clarified, respectively. The cutoff frequency of the piezoelectric device is also studied. Moreover, MEMS/NEMS hybrids specified by double/single-clamped ZnO quantum wire micro/nano-electromechanical resonator hybrids are proposed. Through a comprehensive numerical simulation, it is revealed that the rich nonlinear dynamics of the resonator can be subtly transferred to the piezoelectric device, and the chaotic transmission in the piezoelectric device can arise in two-dimensional parameter space with respect to time and incident electron energy. Therefore, the hybrids are endowed with the ability to detect amplitude changes by measuring ultra-sensitive quantum tunneling current. The study sheds light on developing quantum piezotronics and its related MEMS/NEMS integrations. [ABSTRACT FROM AUTHOR]

In this work, we aim to establish a theoretical method for modelling the dynamic characteristics of piezotronics and piezo-phototronic devices. By taking the simplest piezotronic device, PN junction as an example, we combine the small signal model and the unified approach to investigate its diffusion capacitance and conductance when it is under both low and high frequency external compressive stresses. This approach is different from the traditional considerations that treat the piezopotential as a static value. Furthermore, we expand the theory into piezo-phototronic devices, e.g., a light emitting diode. The dynamic recombination rate and light emitting intensity are quantitatively calculated under different frequencies of external compressive stresses. [ABSTRACT FROM AUTHOR]

Since thirty years ago in 1982 when the concept of mode localization of the two coupled mechanical structures was introduced, there have been many investigations on this phenomenon, leading to applications in various areas, one of which is focused on transducers. This phenomenon is linked closely to Anderson localization theory in condensed matter physics; in fact, it is regarded as one-dimensional representation of the Anderson localization. Later, the configuration of two coupled mechanical structures has been extended to multiple coupled structures having one or more localized modes. All these investigations have pointed out that a weaker coupling factor will result in stronger mode localization; sometimes, it was noted that the weakest coupling has the greatest localization effect. However, it is not sufficiently precise, as the "weakest" coupling is for the structures that are nearly separate. Here, in this article, we conduct a theoretical and experimental study to unveil that there exists an optimal coupling for coupled mechanical structures at which the energy localization effect reaches to the maximum. [ABSTRACT FROM AUTHOR]