Schottky diode is composed of a metal in contact with a semiconductor. Despite its simple construction, Schottky diode is a tremendously useful component and is omnipresent in modern electronics. Schottky diode fabricated using two-dimensional (2D) materials have attracted major research spotlight in recent years due to their great promises in practical applications such as transistors, rectifiers, radio frequency generators, logic gates, solar cells, chemical sensors, photodetectors, flexible electronics and so on.
The understanding of 2D material-based Schottky diode is, however, plagued by multiple mysteries. Several theoretical models have co-existed in the literatures and a model is often selected a priori without rigorous justifications. It is not uncommon to see a model, whose underlying physics fundamentally contradicts with the physical properties of 2D materials, being deployed to analyse a 2D material Schottky diode.
Reporting in Physical Review Letters, researchers from the Singapore University of Technology and Design (SUTD) have made a major step forward in resolving the mysteries surrounding 2D material Schottky diode. By employing a rigorous theoretical analysis, they developed a new theory to describe different variants of 2D-material-based Schottky diodes under a unifying framework. The new theory lays down a foundation that helps to unite prior contrasting models, thus resolving a major confusion in 2D material electronics.
"A particularly remarkable finding is that the electrical current flowing across a 2D material Schottky diode follows a one-size-fits-all universal scaling law for many types of 2D materials," said first-author Dr. Yee Sin Ang from SUTD.
Universal scaling law is highly valuable in physics since it provides a practical "Swiss knife" for uncovering the inner workings of a physical system. Universal scaling law has appeared in many branches of physics, such as semiconductor, superconductor, fluid dynamics, mechanical fractures, and even in complex systems such as animal life span, election results, transportation and city growth.
The universal scaling law discovered by SUTD researchers dictates how electrical current varies with temperature and is widely applicable to broad classes of 2D systems including semiconductor quantum well, graphene, silicene, germanene, stanene, transition metal dichalcogenides and the thin-films of topological solids.
"The simple mathematical form of the scaling law is particularly useful for applied scientists and engineers in developing novel 2D material electronics," said co-author Prof. Hui Ying Yang from SUTD.
The scaling laws discovered by SUTD researchers provide a simple tool for the extraction of Schottky barrier height - a physical quantity critically important for performance optimisation of 2D material electronics.
"The new theory has far reaching impact in solid state physics," said co-author and principal investigator of this research, Prof. Lay Kee Ang from SUTD, "It signals the breakdown of classic diode equation widely used for traditional materials over the past 60 years, and shall improve our understanding on how to design better 2D material electronics."
Universal Scaling Laws in Schottky Heterostructures Based on Two-Dimensional Materials
Yee Sin Ang, Hui Ying Yang, and L. K. Ang
Phys. Rev. Lett. 121, 056802 – Published 1 August 2018
DOI: https://doi.org/10.1103/PhysRevLett.121.056802
Contact information:
Prof. Ang Lay Kee @ Ricky
SUTD Engineering Product Development
ricky_ang@sutd.edu.sg
Tel: +65 6499 4558
URL: http://people.sutd.edu.sg/ricky_ang/
Singapore University of Technology and Design (SUTD)
#2DMaterials #Nanoelectronics #Physics
Pyrene-modified polyionic complex vesicles, or Pyr-PICsomes, convert hydrostatic pressure into measurable fluorescence. Crosslinking density tunes membrane stiffness, which governs sensing behavior: soft vesicles give strong excimer-to-monomer ratio changes from 0.1 to 50 MPa, while stiff membranes respond through fluorescence lifetime, suiting lifetime imaging.
Ar/O₂ plasma treatment generates supranano α-Fe, Fe₃O₄, SiO₂ and Fe₂O₃ precipitates just 0.8–2.5 nm across amorphous powder surfaces, creating nucleation sites that ease magnetic-moment reversal. The resulting soft magnetic composite combines 0.13 Oe coercivity, 37.3 permeability, 185 emu g⁻¹ saturation magnetization and 191.18 kW m⁻³ core loss at 1 MHz and 20 mT. The surface route avoids bulk composition changes, aiding scale-up for high-frequency inductors and power chokes.
Researchers at MANA have introduced a theoretical framework that extracts hidden disorder from complex photoluminescence spectra in twisted MoSe2/WSe2 moiré heterostructures, bypassing unreliable peak-by-peak analysis. By tracking how simple descriptors like peak and average energy vary spatially, the work reveals a hierarchy of disorder, from micrometer-scale background variations to localized exciton-trapping defects.
