Enabling Active Nanotechnologies by Phase Transition: From Electronics, Photonics to Thermotics

Abstract

Phase transitions can occur in certain materials such as transition metal oxides (TMOs) and chalcogenides when there is a change in external conditions such as temperature and pressure. Along with phase transitions in these phase change materials (PCMs) come dramatic contrasts in various physical properties, which can be engineered to manipulate electrons, photons, polaritons, and phonons at the nanoscale, offering new opportunities for reconfigurable, active nanodevices. In this review, we particularly discuss phase-transition-enabled active nanotechnologies in nonvolatile electrical memory, tunable metamaterials, and metasurfaces for manipulation of both free-space photons and in-plane polaritons, and multifunctional emissivity control in the infrared (IR) spectrum. The fundamentals of PCMs are first introduced to explain the origins and principles of phase transitions. Thereafter, we discuss multiphysical nanodevices for electronic, photonic, and thermal management, attesting to the broad applications and exciting promises of PCMs. Emerging trends and valuable applications in all-optical neuromorphic devices, thermal data storage, and encryption are outlined in the end.

NbTe4 Phase‐Change Material: Breaking the Phase‐Change Temperature Balance in 2D Van der Waals Transition‐Metal Binary Chalcogenide

“…This incongruent melting behavior is similar to the conventional PCMs such as GST. [ 23 ] The thermal stability of the amorphous phase is an important factor in data retention in the PCRAM application. Thus, the thermal stability of the as‐deposited film was also evaluated by DSC measurements at various heating rates based on the Ozawa method.…”

Machine Learning Aided Design and Optimization of Thermal Metamaterials

“…There have been already a couple of review articles in the optical and electromagnetic metamaterials including the meta surfaces. − Therefore, in this article we focus on the optimization and inverse design of thermal metamaterials using machine learning techniques, particularly gradient-free optimization algorithms. The research of thermal metamaterials has gained a great momentum in past decade, mainly due to its potential applications in thermal management and control in microelectronic chips/devices and batteries used in electronic vehicles. − …”

Greatly Enhanced Resonant Exciton‐Trion Conversion in Electrically Modulated Atomically Thin WS2 at Room Temperature

“…Multiple mechanisms and materials [11,12] have been reported for tunable and reconfigurable metasurfaces with pros and cons for different applications. For example, chalcogenide-based phase change materials (PCMs) [13] could have large optical constant change responding to electrical pulse [14][15][16] besides to laser pulse or thermal heating, [17,18] but with limitations on the materials loss in the visible range and high-power consumption in reversable tuning mechanism. In fact, the excitonic features in semiconductors are closely linked to their optical behaviors and can be tuned by various methods, such as chemical doping, [19] electrical gating, [20][21][22] and thermal effect, [23] etc.…”