ABSTRACT
With the explosion of data-centric applications, new in-memory computing technologies, based on nonvolatile memory devices, have become competitive due to their merged logic-memory functionalities. Herein, employing first-principles quantum transport simulation, we theoretically investigate for the first time the electronic and contact properties of two types of monolayer (ML)-MoS2 ferroelectric field-effect transistors (FeFETs) integrated with ferroelectric BiAlO3(0001) (BAO(0001)) polar surfaces. Our study finds that the interfacial properties of the investigated partial FeFET devices are highly tunable by switching the electric polarization of the ferroelectric BAO(0001) dielectric. Specifically, the transition from quasi-Ohmic to the Schottky contact, as well as opposite contact polarity of respective n-type and p-type Schottky contact under two polarization states can be obtained, suggesting their superior performance metrics in terms of nonvolatile information storage. In addition, due to the feature of (quasi-)Ohmic contact in some polarization states, the explored FeFET devices, even when operating in the regular field-effect transistor (FET) mode, can be extremely significant in realizing a desirable low threshold voltage and interfacial contact resistance. In conjunction with the formed van der Waals (vdW) interfaces in ML-MoS2/ferroelectric systems with an interlayer, the proposed FeFETs are expected to provide excellent device performance with regard to cycling endurance and memory density.
ABSTRACT
In recent years, α-In2Se3 has attracted great attention in miniaturizing nonvolatile random memory devices because of its room temperature ferroelectricity and atomic thickness. In this work, we construct two-dimensional (2D) van der Waals (vdW) heterostructures α-In2Se3/MoS2 with different ferroelectric polarization and design a 2D graphene (Gr)/In2Se3/MoS2/Gr ferroelectric tunnel junction (FTJ) with the symmetric electrodes. Our calculations show that the band alignment of the heterostructures can be changed from type-I to type-II accompanied by the reversal of the ferroelectric polarization of In2Se3. Furthermore, the ferroelectricity persists in Gr/In2Se3/MoS2/Gr vdW FTJs, and the presence of dielectric layer MoS2 in the FTJs enables the effective modulation of the tunneling barrier by altering the ferroelectric polarization of α-In2Se3, which results in two distinct conducting states denoted as "ON" and "OFF" with a large tunneling electroresistance (TER) ratio exceeding 105%. These findings suggest the importance of ferroelectric vdW heterostructures in the design of FTJs and propose a promising route for applying the 2D ferroelectric/semiconductor heterostructures with out-of-plane polarization in high-density ferroelectric memory devices.
ABSTRACT
Toll-like receptors (TLRs) are a large family of pattern recognition receptors (PRRs) that play a critical role in innate immunity. TLRs are activated when they recognize microbial associated molecular patterns (MAMPs) of bacteria, viruses, or fungus. In the present study, two TLRs were isolated from the mantle of the hard-shelled mussel (Mytilus coruscus) and designated McTLR2 and McTLR3 based on their sequence similarity and phylogenetic clustering with Crassostrea gigas, CgiTLR2 and CgiTLR3, respectively. Quantitative RT-PCR analysis demonstrated that McTLR2 and McTLR3 were constitutively expressed in many tissues but at low abundance.
Subject(s)
Hemocytes/immunology , Immunity, Innate/genetics , Mytilus/genetics , Mytilus/immunology , Toll-Like Receptors/genetics , Toll-Like Receptors/immunology , Amino Acid Sequence , Animals , Gene Expression Profiling , Hemocytes/metabolism , Phylogeny , Sequence Alignment , Toll-Like Receptors/chemistryABSTRACT
Halon-1301 (CF3Br) can make Br radicals with UV radiation, which poses a great threat to the ozone layer in the atmosphere. Necessary methods should be taken for the degradation of the exhausts of Halon-1301. In this paper, density functional (DFT) theory at B3LYP/6-311G++(d,p) level are employed for the study of dissociation properties and spectra of Halon-1301 in external electric field, including bond length, total energy, HOMO-LUMO energy gap, infrared spectra and dissociation potential energy surface (PES). The obtained results show that, with gradually increasing the external field from 0 to 0.03 a.u. along the molecular axis Z (CBr bond direction), the total energy decreases, while the dipole moment decreases at the beginning and then increases. With the climbing of the field, HOMO-LUMO energy gap increases, and CBr bond length increases while CF bond length decreases. The variations of vibrational frequency and intensity of molecular IR spectra in external electric field are also investigated. Further studies show that with increasing the external electric field from 0 to 0.03 a.u., the dissociation PES along CBr bond becomes unbound with disappearing of the barrier for the dissociation. The external electric field of 0.03 a.u. is sufficient to induce the degradation of CF3Br with CBr bond breaking. Such results provide an important reference for the degradation of Halons via the external electric field.
Subject(s)
Bromochlorofluorocarbons/chemistry , Electricity , Models, Molecular , Molecular Conformation , Quantum Theory , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman , Thermodynamics , VibrationABSTRACT
F16 is a mitochondria-targeted, broad-spectrum anticancer agent in the pre-clinic cancer therapy. Here we developed two fluorescent isomers of F16 (o-F16 and m-F16) with entirely different photophysical properties, uncoupling activity, and cytotoxicity by merely modifying the linking orientation of pyridinium and indole units. Individually, o-F16 acted as a strong uncoupler to reduce the mitochondrial respiration efficiency, while m-F16 could hardly uncouple the mitochondrial respiration due to its poor proton dissociation capability. Owing to their intrinsic fluorescence, o-F16 and m-F16 could specifically image mitochondria in the green and red channel, respectively. This work could provide useful information for the development of uncouplers and design of mitochondrial-targeted drugs.