The kinetics for Schottky defect (Tl and Br vacancy pair) formation and annihilation in ionically conducting TlBr are characterized through a temperature induced conductivity relaxation technique. Near room temperature, defect generation-annihilation was found to take on the order of hours before equilibrium was reached after a step change in temperature, and that mechanical damage imparted on the sample rapidly increases this rate. The rate limiting step to Schottky defect formation-annihilation is identified as being the migration of lower mobility Tl (versus Br), with an estimate for source-sink density derived from calculated diffusion lengths. This study represents one of the first investigations of Schottky defect generation-annihilation kinetics and demonstrates its utility in quantifying detrimental mechanical damage in radiation detector materials.
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http://dx.doi.org/10.1039/c3cp51043c | DOI Listing |
Nano Lett
January 2025
Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception, Institute of Optoelectronics, Department of Materials Science, Fudan University, Shanghai 200433, China.
Achieving high mobility while minimizing off-current and static power consumption is critical for applications of two-dimensional field-effect transistors. Herein, a selenium (Se) sacrificial layer is introduced between the rhenium sulfide (ReS) semiconductor and source/drain electrode. With the Se layer and postannealing process, the ReS transistor significantly decreases the off-state current with a substantial increase in the on-state current density.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
Two-dimensional van der Waals (vdW) layered materials not only are an intriguing fundamental scientific research platform but also provide various applications to multifunctional quantum devices in the field-effect transistors (FET) thanks to their excellent physical properties. However, a metal-semiconductor (MS) interface with a large Schottky barrier causes serious problems for unleashing their intrinsic potentials toward the advancements in high-performance devices. Here, we show that exfoliated vdW Dirac semimetallic PtTe can be an excellent electrode for electrons in MoS FETs.
View Article and Find Full Text PDFMater Horiz
December 2024
Walter Schottky Institute, Technical University of Munich, 85748 Garching, Germany.
Semiconducting ternary nitrides are a promising class of materials that have received increasing attention in recent years, but often show high free electron concentrations due to the low defect formation energies of nitrogen vacancies and substitutional oxygen, leading to degenerate n-type doping. To achieve non-degenerate behavior, we now investigate a family of amorphous calcium-zinc nitride (Ca-Zn-N) thin films. By adjusting the metal cation ratios, we demonstrate band gap tunability between 1.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China.
Hybrid lead halide perovskites are promising materials for photovoltaic applications due to their exceptional optoelectronic properties. Here, we investigate the impact of Schottky defects─specifically PbI(V) and CHNHI (V) vacancies─on nonradiative recombination in CHNHPbI using time-dependent density functional theory and nonadiabatic (NA) molecular dynamics. Our results reveal that Schottky defects do not alter the fundamental bandgap or introduce trap states but instead distort the surrounding lattice, localizing the hole distribution.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632, Republic of Singapore.
Using density functional theory (DFT) calculations we thoroughly explored the influence of grain boundaries (GBs) in monolayer MoS composed of S-polar (S5|7), Mo-polar (Mo5|7), and (4|8) edge dislocation, as well as an edge dislocation-double S vacancy complex (S4|6), and a dislocation-double S interstitial complex (S6|8), respectively, on the electronic properties of MoS and the Schottky barrier height (SBH) in MoS@Au heterojunctions. Our findings demonstrate that GBs formed by edge dislocations can significantly reduce the SBH in defect-free MoS, with the strongest effect for zigzag (4|8) GBs (-20% reduction) and the weakest for armchair (5|7) GBs (-10% reduction). In addition, a larger tilt angle in the GBs leads to a more pronounced decrease in the SBH, suggesting that the modulation of SBH in the MoS@Au heterostructure and analogous systems can be accomplished by GB engineering.
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