Ali Javey (Advisor)

Tellurium is a narrow-gap, p-type semiconductor with promising potential for future electronic and optoelectronic devices. Te’s band gap can be tuned from 0.31 eV in bulk form to 1.04 eV in monolayer form. Unlike many other competing 2D semiconductors, Te is air-stable and can be deposited on a substrate of choice by thermal evaporation or solution synthesis. Photodetectors based on solution-synthesized Te nanoflakes have already been demonstrated, with specific detectivity in near-IR at or above 10^9 Jones. However, solution-synthesis of Te nanoflakes is not scalable, and...

Gas sensing has long been an area of academic and industrial interest. However, state of the art sensors still lack selectivity and sensitivity when it comes to differentiating gases of similar compositions. In this work, we explore methods to create multiplexed gas sensors that can differentiate these mixtures with high accuracy and long-term stability.

Project is currently funded by: Federal

Midwave infrared (MWIR) is significant for applications such as sensing, imaging, and spectroscopy. Traditional materials in this wavelength range, III-V and II-VI semiconductors, has poor performance due to their high Auger recombination rate and large dark currents. Due to the better properties of black phosphorus (BP) such as its low Auger recombination coefficient, BP-based mid-infrared light emitters and detectors have shown to outperform the state-of-the-art commercial devices. However, the scalability of these devices remains questionable because of the limitations of...

A weak van der Waals (vdW) force in layered materials enables their isolation into thin flakes through mechanical exfoliation while sustaining their intrinsic electronic and optical properties. Here, we introduce a universal roll-printing method capable of producing vdW multilayer films on wafer-to-meter scale. This process uses sequential exfoliation and transfer of layered materials from the powder sources to target substrates through a repeated rolling of a cylindrical metal drum. We achieve uniformly coated films with a library of vdW powders on various mechanically rigid and...