Kinetic Monte Carlo simulations of optimization of self-assembly quantum rings growth strategy based on substrate engineering

In this paper, the kinetic Monte Carlo simulations of the self-assembly quantum rings （QRs） based on the substrate engineering, which is related to the eventual shape of the formed quantum ring, are implemented. According to the simulation results, the availability of the QR with tunable size and the formation of smooth shape on the ideal flat substrate are checked. Through designing the substrate engineering, i.e., changing the depth, the separation and the ratio between the radius and the height of the embedded inclusions, the position and size of QR can be controlled and eventually the growth strategy of optimizing the self-assembly QRs is accomplished.

Strain of 2D materials via substrate engineering

Two-dimensional(2D)materials have received extensive attention in the fields of electronics,optoelectronics,and magnetic devices attributed to their unique electronic structures and physical properties.The application of strain is a simple and effective strategy to change the lattice structure of 2D materials thus modulating their physical properties,which further facilitate their applications in carrier mobility transistor,magnetic sensor,single-photon emitter etc.In this short review,we focus on the strain applied via substrate engineering.Firstly,the relationship between the strain and physical properties has been summarized.Secondly,the methods for achieving substrate engineering-induced strain have been demonstrated.Finally,the latest applications of strained 2D materials have been introduced.In addition,the future challenges and development prospects of strain-modulated 2D materials have also been proposed.

Growth of Tellurium Nanobelts on h-BN for p-type Transistors with Ultrahigh Hole Mobility

The lack of stable p-type van der Waals(vdW)semiconductors with high hole mobility severely impedes the step of low-dimensional materials entering the industrial circle.Although p-type black phosphorus(bP)and tellurium(Te)have shown promising hole mobilities,the instability under ambient conditions of bP and relatively low hole mobility of Te remain as daunting issues.Here we report the growth of high-quality Te nanobelts on atomically flat hexagonal boron nitride(h-BN)for high-performance p-type field-effect transistors(FETs).Importantly,the Te-based FET exhibits an ultrahigh hole mobility up to 1370 cm^(2) V^(−1) s^(−1) at room temperature,that may lay the foundation for the future high-performance p-type 2D FET and metal-oxide-semiconductor(p-MOS)inverter.The vdW h-BN dielectric substrate not only provides an ultra-flat surface without dangling bonds for growth of high-quality Te nanobelts,but also reduces the scattering centers at the interface between the channel material and the dielectric layer,thus resulting in the ultrahigh hole mobility.

Batch fabrication of MoS_(2) devices directly on growth substrates by step engineering

Monolayer molybdenum disulfide(MoS_(2))has emerged as one of the most promising channel materials for next-generation nanoelectronics and optoelectronics owing to its atomic thickness,dangling-bond-free flat surface,and high electrical quality.Currently,high-quality monolayer MoS_(2)wafers are primarily grown on sapphire substrates incompatible with conventional device fabrication,and thus transfer processes to a suitable substrate are typically required before the device can be processed.Here,we demonstrate the batch production of transfer-free MoS2 top-gate devices directly on sapphire growth substrates via step engineering.By introducing substrate steps on growth substrate sapphire,high-κdielectric layers with superior quality and uniform can be directly deposited on the epitaxially grown monolayer MoS_(2).For the substrate with a maximum step density of 100μm^(−1),the gate capacitance can reach~1.87μF∙cm^(−2),while the interface trap state density(Dit)can be as low as~7.6×10^(10)cm^(−2)∙eV^(−1).The direct deposition of high-quality dielectric layers on grown monolayer MoS2 enables the batch fabrication of top-gate devices devoid of transfer and thus excellent device yield of>96%,holding great promise for large-scale twodimensional(2D)integrated circuits.

Structure-based design,synthesis of novel probes for cytochrome P450 OleT

Cytochrome P450 OleT_(SA),a new cytochrome P450 enzyme from Staphylococcus aureus,catalyzes the oxidative decarboxylation and hydroxylation of fatty acids to generate terminal alkenes and fatty alcohols.The mechanism of this bifurcative chemistry remains largely unknown.Herein,a class of derivatized fatty acids were synthesized as probes to investigate the effects of substrate structure on the product type of P450 OleT_(SA).The results demonstrate that the fine-tuned structure of substrates,even in a remote distance from the carboxyl group,significantly regulates OleT catalyzed decarboxylation/hydroxylation reactions.Molecular docking analysis indicated the potential interactions between the carboxylate groups of different probes and the enzyme active center which was attributed to the bifurcative chemistry.