Semiconductor Engineering.:. System bits: September 25

Schottky Diodes: A 2D Hardware Equation for All Governing
Specifying the right materials for the heterostructure of 2D Schottky diodes – made of a metal touching a semiconductor – means that designers have to go through sometimes conflicting theoretical models to select materials. "It's not uncommon to see a model whose underlying physics fundamentally contradicts the physical properties of 2D materials, being analyzed to analyze a 2D Schottky diode," says an article from L & 39. University of Technology and Design Singapore (SUTD).

SUTD researchers have now discovered a unique equation that could help dispel some of the confusion of models to simplify the design of 2D Schottky diodes. The researchers say the equation is broadly applicable to large classes of 2D systems, including the semiconductor quantum well, graphene, silene, germanene, stanene, transition metal dichalcogenides, and layers. thin topological solids.

By finding similarities between carrier transport – electrical current – flowing through 2D Schottky diodes, the researchers found a universal scaling law describing different variants of Schottky diodes based on 2D materials. They found that the reverse saturation current was universally scaled with temperature and its relationship to vertical and lateral heterostructures. The height of the Schottky barrier can then be calculated.

"The universal scaling laws signal the decomposition of scaling β = 2 in the classic diode equation widely used over the last sixty years," researchers conclude. SUTD in their article published in Physical Review Letters. "Our model solves some of the contradictory results of earlier work and is consistent with recent experiences."

Learn more at the University of Technology and Design Singapore: Research News. Read the SUTD article published in Physical Review Letters, Universal Descaling Laws in Schottky Heterostructures Based on Two Dimensional Materials.

"Maxwell's Demon" Helps Researchers Move to Quantum Computers
Penn State researchers have said they have reduced entropy in a network of over-cooled atoms, which is one step closer to the quantum computer. Using a laser to trap the atoms, the researchers were able to manipulate them into organized blocks. The uncharged atoms of the system could be used as "quantum bits" or "qubits" one day to perform calculations and code data under quantum mechanical phenomena that allow them to be in several states simultaneously.

Researchers can move atoms in 125 positions arranged in 5 x 5 x 5 cube. "The organization of atoms into a compact 3D grid allows us to integrate a large number of atoms in a restricted area and to make calculations easier and more effective, "said David Weiss, professor of physics at Penn State.

In describing the discovery, the researchers invoked a thought experiment of the 1870s called Maxwell's Demon. The demon is supposed to stop the entropy, which, according to the second law of thermodynamics, always increases, usually, in a system. The entropy can also be in a state of equilibrium or can be negative only in some cases when something is acting on it. The second law of thermodynamics makes perpetual motion impossible, but the experience of demonic thought imagined that the demon created a kind of perpetual motion. Researchers say they can play the role of the devil. To understand the analogy, read more here.

A new way of measuring quantum bits focuses on microwave photons
The way researchers currently measure qubits – or quantum bits – will not evolve to the millions of qubits that quantum processors will eventually produce. Researchers from Syracuse University's Plourde Group, in collaboration with collaborators at the University of Wisconsin (UW) -Madison, have published an article detailing a new way of measuring the qubits that can handle this load. job.

To measure qubits, researchers are now using low-noise cryogenic amplifiers and a lot of microwave equipment at room temperature. The 50 qubits that Google and IBM have removed from their quantum processors are nowhere near hundreds of times needed to do useful work – and they have had to cool the superconducting microwave circuits to a level close to absolute zero.

"We are focusing on the detection of microwave photons," said Britton Plourde, professor of physics at Syracuse University and editor of IEEE Transactions on Applied Superconductivity, in a press release. "Our approach replaces the need for a cryogenic amplifier and could be expanded, in a simple way, to remove much of the material needed at room temperature." Researchers in the Plourde group use a microwave photo counter, whose "measurement fidelity to a rough shot is 92%".

Unlike digital bits, which have only one state at a time, qubits can exist in two states at a time. The hope is that quantum computing can one day solve problems that even supercomputers can not solve.

The researchers published their findings in Science magazine. Read more here.