Novel Devices Based on Quantum Carbon Dots Exhibiting Non-Linear Current-Voltage Characteristic

As the field of semiconductor technology rapidly evolves, the need for advanced 3D integration solutions becomes increasingly critical. Traditional two-dimensional designs are reaching their physical limits as devices continue to shrink, making it essential to explore new approaches to hardware design. One area of interest in 3D integration is surge suppression using alternative materials and designs. In this work, we introduce a novel composite surge arrestor device constructed by crudely depositing an epoxy paste filled with carbon quantum dots (CQDs) on to a interdigitated electrodes geometry. When subjected to electrical bias of 5V, 2mA at room temperature, this device displays a variety of nonlinear current-voltage (IV) characteristics, including behaviors typical of a varistor, Schottky diodes, tunneling diodes, and Coulomb blockade phenomena. This variety of nonlinear responses is influenced by several factors, including the design of the interdigitated electrodes, the molecular additives in the epoxy matrix, and the CQDs. The inclusion of nano metal oxide and chemical dopants and CQDs within the epoxy matrix enables electrochemical interactions with the interdigitated electrodes, modifying electron trapping behavior. In addition to our experimental results, we present theoretical models that not only validate observations but also explain electron traps to quantum dot interactions which help create observed nonlinear behaviors. Initial testing of the samples consistently yields nonlinearity factors (α-values) between 6 and 8, with the highest recorded value reaching 15. However, after two or more tests on any one sample, the sample will exhibit more monotonic behavior trending towards an α-value of 1 - 2, suggesting a shift in their electrical properties. Under bias, these electron traps open and close, generating the nonlinear IV curves seen during initial tests. However, further testing beyond test 2 on any one sample shows that this nonlinear behavior diminishes, indicating that the electron traps in the epoxy matrix permanently close in a way that results in a stabilized monotonic response. The precise mechanism behind the so far irreversible change in the sample could be a form of equilibrium in electron traps being occupied between the epoxy side and electrode side of the samples. Furthermore, the nonlinear behaviors observed do not appear on more traditionally made components in conjunction with our epoxy CQD matrix indicating that the electrode architecture plays a significant role in producing nonlinear IV curves. The presence of various nonlinear IV curves further increase the utility of the electrode with deposited epoxy matrix as this opens the door for replacing not only varistors but types of diodes as well. Additionally, the observation of the Coulomb blockade phenomenon in some samples poses an opportunity to potentially obtain higher α-values where the IV curve displays a staircase effect acting as short cut, rather than curving in the traditional sense of a varistor and diode. This innovative solution presents one way a more compact and efficient 3D integrated varistor component could replace bulkier constructs utilized now, further enabling streamlined and densely packed hardware architectures.