Ultra-Fast and Exotic Nanoelectronics
Overview:
Various nanoelectronic structures are being proposed on a frequent basis. These novel structures yet to be investigated. In our group, we investigate different structures of field effect transistor while characterizing the performance of these nanoelectronics for an eco-friendly, and low power electronics and sensors.
Emerging Van de Waals - Field-Effect-Transistors (VdW-FETs)
Transistors based on 2D materials still suffer from poor contact with source and drain electrodes. Conventional fabrication processes can induce defect states, which in turn affect the intrinsic electronic properties of 2D materials. There have been extensive studies on improving the performance of 2D materials. These studies show that Schottky barrier between VdW material and contact electrode can be significantly lowered compared to conventional methods, allowing the probing of electronic states and properties of VdW material.. Here, we fabricate VdW-FETs and a customized deposition method by aligning VdW material to a pre-fabricated source and drain electrodes, minimizing lattice structural defects. Using contact engineering techniques, it is possible to modulate the electron transport of these 2D materials. For example, one newly discovered method is induction of a large thermal energy pulse on the transistor. The figure on the left shows how this thermal energy pulse can modulate the maximum conductivity, causing radical changes in the measured Ion/Ioff ratio, the sub-threshold swing, and the contract resistance. In our group, we use complementary methods to increase the device performance
Manipulation of Electron Transport using Laser Irradiation: An Additive Manufacturing Approach
Selective doping and thickness manipulation at the nanoscale can be challenging. Nevertheless, laser based techniques have proven to be an effective method to manipulate low dimensional materials with high precision. In this work, we use laser based manufacturing techniques on low dimensional materials to alter the material electronic properties at the atomic level. For example, HfSe2 is a promising material with band gap close to silicon. HfSe2 based FETs are fabricated and laser irradiated selectively to observe the conductivity switch which occurs after repetitive laser irradiation. Moreover, the material structural properties is tested before and after laser irradiation to assess the effect of this process on the channel material.
