Ultra-thin van der Waals crystals as semiconductor quantum wells

Abstract

Control over the electronic spectrum at low energy is at the heart of the functioning of modern advanced electronics: high electron mobility transistors, semiconductor and Capasso terahertz lasers, and many others. Most of those devices rely on the meticulous engineering of the size quantization of electrons in quantum wells. This avenue, however, hasn't been explored in the case of 2D materials. Here we transfer this concept onto the van der Waals heterostructures which utilize few-layers films of InSe as quantum wells. The precise control over the energy of the subbands and their uniformity guarantees extremely high quality of the electronic transport in such systems. Using novel tunnelling and light emitting devices, for the first time we reveal the full subbands structure by studying resonance features in the tunnelling current, photoabsorption and light emission. In the future, these systems will allow development of elementary blocks for atomically thin infrared and THz light sources based on intersubband optical transitions in few-layer films of van der Waals materials.

12 pages, 3 figures

References in corpus (9)

• 2D materials and van der Waals heterostructures
• Light-emitting diodes by bandstructure engineering in van der Waals heterostructures
• High Electron Mobility, Quantum Hall Effect and Anomalous Optical Response in Atomically Thin InSe
• Resonantly hybridised excitons in moiré superlattices in van der Waals heterostructures
• Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials
• Electrons and phonons in single layers of hexagonal indium chalcogenides from ab initio calculations
• Electronic and optical properties of two-dimensional InSe from a DFT-parameterized tight-binding model
• Indirect to direct gap crossover in two-dimensional InSe revealed by ARPES
• Observing imperfection in atomic interfaces for van der Waals heterostructures