Directly Linking Low-Angle Grain Boundary Misorientation to Device Functionality for GaAs Grown on Flexible Metal Substrates.

A new growth method to make highly oriented GaAs thin films on flexible metal substrates has been developed, enabling roll-to-roll manufacturing of flexible semiconductor devices. The grains are oriented in the <001> direction with <1° misorientations between them, and they have a comparable mobility to single-crystalline GaAs at high doping concentrations. At the moment, the role of low-angle grain boundaries (LAGBs) on device performance is unknown.

Over 15 MA/cm of critical current density in 4.8 µm thick, Zr-doped (Gd,Y)BaCuO superconductor at 30 K, 3T.

An Advanced MOCVD (A-MOCVD) reactor was used to deposit 4.8 µm thick (Gd,Y)BaCuO tapes with 15 mol% Zr addition in a single pass. A record-high critical current density (J ) of 15.

J (4.2 K, 31.2 T) beyond 1 kA/mm of a ~3.2 μm thick, 20 mol% Zr-added MOCVD REBCO coated conductor.

A main challenge that significantly impedes REBaCuO (RE = rare earth) coated conductor applications is the low engineering critical current density J because of the low superconductor fill factor in a complicated layered structure that is crucial for REBaCuO to carry supercurrent. Recently, we have successfully achieved engineering critical current density beyond 2.0 kA/mm at 4.

High-Performance Flexible Thin-Film Transistors Based on Single-Crystal-like Silicon Epitaxially Grown on Metal Tape by Roll-to-Roll Continuous Deposition Process.

Single-crystal-like silicon (Si) thin films on bendable and scalable substrates via direct deposition are a promising material platform for high-performance and cost-effective devices of flexible electronics. However, due to the thick and unintentionally highly doped semiconductor layer, the operation of transistors has been hampered. We report the first demonstration of high-performance flexible thin-film transistors (TFTs) using single-crystal-like Si thin films with a field-effect mobility of ∼200 cm/V·s and saturation current, I/l > 50 μA/μm, which are orders-of-magnitude higher than the device characteristics of conventional flexible TFTs.

Toward Superconducting Critical Current by Design.

A new critical-current-by-design paradigm is presented. It aims at predicting the optimal defect landscape in superconductors for targeted applications by elucidating the vortex dynamics responsible for the bulk critical current. To this end, critical current measurements on commercial high-temperature superconductors are combined with large-scale time-dependent Ginzburg-Landau simulations of vortex dynamics.