Microwave-assisted Low-temperature Growth of Thin Films in Solution

Abstract

Thin films find a variety of technological applications. Assembling thin films from atoms in the liquid phase is intrinsically a non-equilibrium phenomenon, controlled by the competition between thermodynamics and kinetics. We demonstrate here that microwave energy can assist in assembling atoms into thin films directly on a substrate at significantly lower temperatures than conventional processes, potentially enabling plastic-based electronics. Both experimental and electromagnetic simulation results show microwave fields can selectively interact with a conducting layer on the substrate despite the discrepancy between the substrate size and the microwave wavelength. The microwave interaction leads to localized energy absorption, heating, and subsequent nucleation and growth of the desired films. Electromagnetic simulations show remarkable agreement with experiments and are employed to understand the physics of the microwave interaction and identify conditions to improve uniformity of the films. The films can be patterned and grown on various substrates, enabling their use in widespread applications.

Recent advances in low-temperature solution-processed oxide backplanes

“…Moreover, the applied microwave energy can selectively heat-layered materials by tuning the microwave wavelength to the preferential energy absorption of the high dielectric/ohmic-loss material [6]. Especially in solution processing, microwave annealing is more useful because the microwave field can quickly and uniformly heat a solution by directly coupling to molecules within the solution through polarization or conduction.…”

“…Microwave fields can quickly and uniformly heat a solution [5]. In a similar way, HPA enables effective modification of the oxide thin film by supplying thermal energy more efficiently [6]. Ultraviolet irradiation of a sol-gel-processed oxide is also very effective for producing condensed oxide semiconductors with the use of high-energy photons [9].…”

“…Low-temperature TFTs fabrication can also be achieved, using a more physical approach, such as by adjusting the energy source [5][6][7] or adding sources [8][9][10]. Microwave annealing and high-pressure annealing (HPA) were specifically investigated for low-temperature device fabrication in terms of efficient energy supply.…”

Preparation and photocatalytic performance of Bi nanoparticles by microwave-assisted method using ascorbic acid as reducing agent

“…Microwave (MW) assisted method has been widely used to produce nanomaterials with uniform morphology since microwave fields can quickly and uniformly heat a solution by directly coupling to molecules within the solution through polarization or conduction [14][15][16]. As for Bi powders, Bi spheres of micrometer by MW assisted method were reported by Chen's group [6].…”

Magnetic Nanoferrites for RF CMOS: Enabling 5G and Beyond

“…[35][36][37][38] An example of the zinc ferrite thin film deposition process steps along with the description of the microwave reactor is schematically shown in Fig. 3.…”