Towards large area, resonant quantum tunneling diodes by continuous Langmuir transfer of exfoliated 2D materials

Summary 

Atomically thin 2D materials constitute promising building blocks for quantum devices due to their exotic, layer-dependent electronic properties. The ability to stack these materials in alternating layers enables heterostructures to be built in almost limitless combinations and over small enough length scales to observe quantum phenomena. So far though, practical implementation of devices based on layered 2D materials has been limited by the challenges of depositing or transferring single atomically thin layers over large areas and of building multi-layers from different materials. In this project, we expand on our previously demonstrated scalable deposition techniques of films for electrochemical applications and control of defects in exfoliated 2D material flakes to build electronic and optoelectronic-based quantum devices in collaboration with Prof. Na Young Kim’s group. Our central goal is to create large area heterostructures of 2D materials built by sequential Langmuir-Blodgett (LB) deposition. We will use these heterostructures to construct simple proof-of-principle quantum devices such as resonant tunneling diodes (RTDs). The work will include finding optimized film parameters for dense, ultrathin tunneling barriers, development of patterning approaches compatible with sequential LB deposition, and ultimately demonstrating a working single, double, and multi-junction RTDs on flexible substrates. While the RTD is one of the simplest quantum devices that can be fabricated from heterostructures of 2D materials, the methodologies we establish in this project will pave the way for improved THz emitters and detectors, faster transistors and memories, and other devices that rely on similar heterostructures and design.

Figure 1. Large-area, atomically thin coatings of 2D materials prepared by continuous Langmuir deposition. Scanning electron microscopy image (top); Picture of large area coating on glass (bottom).