Effects of V and Gd doping on novel positive colossal electroresistance and quantum transport in PbPdO2 thin films with (002) preferred orientation.

In this work, PbPd0.9V0.1O2 and PbPd0.9Gd0.1O2 thin films with (002) preferred orientation were prepared using a pulsed laser deposition technique. The temperature dependence of resistivities ρI(T) was investigated under various applied DC currents. Colossal electroresistance (CER) effects were found in PbPd0.9V0.1O2 and PbPd0.9Gd0.1O2. It was found that the positive CER values of PbPd0.9V0.1O2 and PbPd0.9Gd0.1O2 reach 3816% and 154% for I = 1.00 µA at 10 K, respectively. In addition, the ρI(T) cycle curves of PbPd0.9V0.1O2 and PbPd0.9Gd0.1O2 thin films showed a critical temperature similar to that of PbPdO2 (Tc = 260 K). Particularly, charge transfer between O1- and O2- was confirmed by in situ XPS. Additionally, based on first-principles calculations and internal electric field models, the CER and magnetic sources in PbPd0.9V0.1O2 and PbPd0.9Gd0.1O2 can be well explained. Finally, it was found that thin film samples doped with V and G ions exhibit weak localization (WL) and weak anti-localization (WAL) quantum transport properties. Ion doping leads to a transition from WAL to WL. The study results indicate that PbPdO2, one of the few oxide topological insulators, can exhibit novel quantum transport behavior after ion doping.

Dietary cholesterol intervention could alleviate the intestinal injury of Oreochromis niloticus induced by plant-based diet via the intestinal barriers.

This study aims to explore the effects of supplementing cholesterol in plant-based feed on intestinal barriers (including physical barrier, chemical barrier, immune barrier, biological barrier) of GIFT strain tilapia (Oreochromis niloticus). Four isonitrogenous and isolipidic diets were prepared as follows: plant-based protein diet (Con group) containing corn protein powder, soybean meal, cottonseed meal, and rapeseed meal, with the addition of cholesterol at a level of 0.6 % (C0.6 % group), 1.2 % (C1.2 % group), and 1.8 % (C1.8 % group), respectively. A total of 360 fish (mean initial weight of (6.08 ± 0.12) g) were divided into 12 tanks with 30 fish per tank, each treatment was set with three tanks and the feeding period lasted 9 weeks. Histological analysis revealed that both the C0.6 % and C1.2 % groups exhibited a more organized intestinal structure, with significantly increased muscle layer thickness compared to the Con group (P < 0.05). Furthermore, in the C1.2 % group, there was a significant up-regulation of tight junction-related genes (claudin-14, occludin, zo-1) compared to the Con group (P < 0.05). 5-ethynyl-2'-deoxyuridine staining results also demonstrated a notable enhancement in intestinal cell proliferation within the C1.2 % group (P < 0.05). Regarding the intestinal chemical barrier, trypsin and lipase activities were significantly elevated in the C1.2 % group (P < 0.05), while hepcidin gene expression was considerably down-regulated in this group but up-regulated in the C1.8 % group (P < 0.05). In terms of the intestinal immune barrier, inflammation-related gene expression levels (tnf-α, il-1ß, caspase 9, ire1, perk, atf6) were markedly reduced in the C1.2 % group (P < 0.05). Regarding the intestinal biological barrier, the composition of the intestinal microbiota indicated that compared to the Con group, both the 0.6 % and 1.2 % groups showed a significant increase in Shannon index (P < 0.05). Additionally, there was a significant increase in the abundance of Firmicutes and Clostridium in the C1.2 % group (P < 0.05). In summary, supplementation of 1.2 % cholesterol in the plant-based diet exhibits the potential to enhance intestinal tight junction function and improve the composition of intestinal microbiota, thereby significantly promoting tilapia's intestinal health.

Effects of Mn doping on electronic and quantum transport in PbPdO2 thin films.

PbPdO2, a gapless semiconductor, can be transformed into a spin gapless semiconductor structure by magnetic ion doping. This unique band-gap structure serves as the foundation for its distinctive physical properties. In this study, PbPd1-xMnxO2 (x = 0.05, 0.1, 0.15) thin films with (002) preferred orientation were prepared by laser pulse deposition (PLD). The structural, electroresistive and magnetoresistive properties were systematically characterized, and the results suggest that films with different Mn doping ratios exhibit a current-induced positive colossal electroresistance (CER), and the CER values of PbPd1-xMnxO2 thin films increase with the increase of Mn doping concentration. The CER values are several fold magnitudes higher compared to those of the previously reported PbPdO2 films possessing identical (002) orientation. Combined with first-principles calculation, the underlying influence mechanism of Mn doping on CER is elucidated. In situ X-ray photoelectron spectroscopy (XPS) demonstrates a close correlation between the positive CER and the band gap change induced by oxygen vacancies in PbPd1-xMnxO2. Additionally, it is observed that Mn-doped films exhibit weak localization (WL) and weak anti-localization (WAL) quantum transport. Moreover, it is found that Mn doping can lead to a transition from WAL to WL; a small amount of Mn doping significantly enhances the weak anti-localization effect. However, with increasing Mn concentration, the WAL effect is conversely weakened. The results of studies suggest strongly that PbPdO2, one of the few oxide topological insulators, can display novel quantum transport behavior by ion doping.

A synergetic promotion of surface stability for high-voltage LiCoO2 by multi-element surface doping: a first-principles study.

The utilization of high-voltage LiCoO2 is an effective approach to break through the bottleneck of practical energy density in lithium ion batteries. However, the structural and interfacial degradations at the deeply delithiated state as well as the associated safety concerns impede the application of high-voltage LiCoO2. Herein, we present a synergetic strategy for promoting the surface stability of LiCoO2 at high voltage by Ti-Mg-Al co-doping and systematically study the effects of the dopants on the surface stability, electronic structure and Li+ diffusion properties of the LiCoO2 (104) surface using first-principles calculations. It is found that Ti, Mg and Al dopants can be facilely introduced into the Co sites of the LiCoO2 (104) surface. Furthermore, the co-doping could significantly stabilize the surface oxygen of LiCoO2 at a high delithiation state. Particularly, by aggregating Ti-Mg-Al co-dopant distribution in the surface layer, surface oxygen loss is dramatically suppressed. In addition, analysis of the electronic structure indicates that Ti-Mg-Al co-doping can enhance the electronic conductivity of the LiCoO2 (104) surface and greatly inhibit the charge deficiency of the superficial lattice O atoms at a highly delithiated state. In spite of a negligible improvement in the surface Li+ diffusion kinetics, the Ti-Mg-Al surface-modified LiCoO2 is expected to exhibit improved electrochemical performance at high voltage due to its superior surface stability. Our results suggest that aggregating Ti, Mg and Al co-dopant distribution in the surface layer is a promising modulation strategy to synergistically promote the surface oxygen stability of LiCoO2 at high voltages.

lncRNA BANCR promotes the colorectal cancer metastasis through accelerating exosomes-mediated M2 macrophage polarization via regulating RhoA/ROCK signaling.

Cancer cells-derived exosomal lncRNAs could modulate the tumorigenesis of colorectal cancer (CRC) via modulating macrophage M2 polarization. However, the clarified mechanism and function of lncRNA BANCR in CRC remains unclear. Exosomes were identified by TEM, NTA, western blot and fluorescent staining. M2 macrophages were identified by CD206 and CD163 expressions using by flow cytometry and RT-qPCR. In addition, the relation between IGF2BP2 and BANCR or RhoA were explored by RIP assay. The malignant behaviors of CRC cells were examined by CCK-8, EdU and transwell assays. Histopathological changes in mice were observed by H&E staining. Silencing of BANCR notably inhibited the proliferation, migration and invasion of CRC cells. SW620 and HCT-15 cells-derived exosomal BANCR positively regulated the macrophage M2 polarization. In addition, exosomal BANCR remarkably enhanced the promoting roles mediated by M2 macrophages on proliferation and invasion in CRC cells. Meanwhile, exosomal BANCR promoted the M2 macrophage polarization via activation of RhoA/Rock pathway by recruiting IGF2BP2. Inhibition of RhoA/Rock pathway reversed exosomal BANCR-mediated macrophages M2 polarization and CRC malignant behaviors in SW620 and HCT-15 cells. Exosomal lncRNA BANCR derived from SW620 and HCT-15 cells promoted the metastasis of CRC via inducing the polarization of M2 macrophages. Thus, BANCR might be a new target for the treatment of CRC.

The interfacial properties of 2D metal-monolayer blue phosphorene heterojunctions and transport properties of their field-effect transistors.

Monolayer blue phosphorene (BlueP) has attracted much interest as a potential channel material in electronic devices. Searching for suitable two-dimensional (2D) metal materials to use as electrodes is critical to fabricating high-performance nanoscale channel BlueP-based field effect transistors (FETs). In this paper, we adopted first-principles calculations to explore binding energies, phonon calculations and electronic structures of 2D metal-BlueP heterojunctions, including Ti3C2-, NbTe2-, Ga(110)- and NbS2-BlueP, and thermal stability of Ti3C2-BlueP heterojunction at room temperature. We also used density functional theory coupled with the nonequilibrium Green function method to investigate the transport properties of sub-5 nm BlueP-based FETs with Ti3C2-BlueP electrodes. Our calculated results indicate that Ti3C2-BlueP has excellent thermal stability and may be used as a candidate electrode material for BlueP-based FETs. The double-gate can more effectively improve the device performance compared with the single-gate. The estimated source leakage current of sub-5 nm transistors reaches up to 369µA µm-1, which is expected to meet the requirements of the international technology roadmap for semiconductors for LP (low-power) devices. Our results imply that 2D Ti3C2may act as an appropriate electrode material for LP BlueP-based FETs, thus providing guidance for the design of future short-gate-length BlueP-based FETs.

A first-principles study of bilayered black phosphorene as a potential anode material for sodium-ion batteries.

Black phosphorene has attracted widespread attention because of its great potential as a high-performance anode material for sodium-ion batteries (SIBs). However, almost all theoretical studies on sodium (Na) atom adsorption and diffusion in it have not taken temperature into account. Actually, the structural stability of an anode material at room temperature is vital in practical applications. In this work, employing first-principles calculations, we investigate the stability of AA-, AB-, AC- and AD-stacked bilayered black phosphorene (BBP) at ground state, and Na adsorption and diffusion within BBPs. Using ab initio molecular-dynamics (AIMD) calculations, dynamic stabilities of pristine BBP and Na-adsorbed BBP systems at room temperature are discussed. Our calculations show that only AB-stacked BBP is stable. Na atoms generally prefer to intercalate within BBP, making all BBPs exhibit metallic properties, which provides good electrical conductivity required for an ideal anode of SIBs. In particular, our AIMD results indicate that the temperature effect on the structural stability of Na-adsorbed BBP could not be neglected. It increases Na capacity loss at room temperature. This provides an important reference for further theoretical and experimental exploration of anode materials for SIBs. Additionally, the AC-stacked structure facilitates Na intercalation within BBP, and Na diffusion exhibits a strong directional preference, diffusing very fast along the zigzag direction. Our results suggest that AC-stacked BBP is a potential anode material of SIBs.

The Zintl phase compounds AEIn2As2 (AE = Ca, Sr, Ba): topological phase transition under pressure.

AEIn2As2 (AE = Ca, Sr, Ba), as a new crucial nonmagnetic thermoelectric candidate, needs to be understood in terms of its potential electronic structure properties and topological characteristics in both experimental and theoretical studies. Here we report that AEIn2As2 with Zintl phases will undergo insulator-metal phase transition and topological quantum phase transition under pressure modulation based on first-principles calculations. Firstly, band inversion occurred between the In(As)-s and As(In)-p states in the structures of AEIn2As2 with the P63/mmc space group in the absence of pressure and identified that they are all non-trivial topological insulators. Next, Bader charge and AIM topology analysis elucidate the nature of pressure-induced chemical bond enhancement. Lastly, we have discovered pressure-controllable band gap closure while the topologically protected surface states disappear, realizing insulator-metal phase transition and topological quantum phase transition. Our research not only enriches the family of topological insulators but also provides a good platform for the study of thermoelectric properties.

Effect of non-magnetic doping on magnetic state and Li/Na adsorption and diffusion of black phosphorene.

Black phosphorene (BP) have aroused great concern because of its great potential for the application in nanoelectronic devices and high-performance anode materials for alkali metal ion batteries (AIBs). However, the absence of magnetism for an ideal BP limits its wide application in spintronic devices which is one of the important nanoelectronic devices, and its application as a high-performance anode material for AIBs is still to be explored. In this paper, we adopt first-principles calculations to explore the effects of B, C, N, O, F, Al, Si and S atom doping on the magnetic state of monolayer BP and Li or Na atom adsorption and diffusion on the BP. Additionally, the thermal stability of the doped BP systems at room temperature is revealed by theab initiomolecular-dynamics calculations. Our calculated results indicate that O and S doping can make the doped BP become a magnetic semiconductor, C and Si doping makes the doped BP be metallic, and B, N, F and Al doping preserves semiconductor property. Moreover, little structural changes and significant decreases of diffusion barriers in armchair direction and slight increases of diffusion barriers in zigzag direction make B-doped BP beneficial as an anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). It reveals that S-doping is suitable for improving the performance of SIBs rather than LIBs. Interestingly, it is found that magnetic states of O- and S-doped BP disappear when Li or Na atoms adsorb on them, whereas Li or Na adsorption on B- and Al-doped BP induces magnetic states of these systems. The analyses indicate that the distinct electron transfer between the dopant atom, adatom and neighboring P atoms, and specific electron configuration of dopant atoms cause the magnetism of the systems. Our results suggest that selecting appropriate composition to dope can effectively manipulate magnetic state and improve Li/Na adsorption and diffusion on the BP. These results may inspire further theoretical and experimental exploration on doped two-dimensional (2D) materials in spintronics and doped 2D promising anode materials for high-performance metal ion batteries.

Discharge of treated Fukushima nuclear accident contaminated water: macroscopic and microscopic simulations.

The diffusion process of the treated Fukushima nuclear accident contaminated water to be discharged into the Pacific Ocean from 2023 is analyzed by two analysis models from macroscopic and microscopic perspectives. Results show that the tritium will spread to the whole North Pacific in 1200 days, which is important to formulate global coping strategies.

First-principles study on the heterostructure of twisted graphene/hexagonal boron nitride/graphene sandwich structure.

In recent years, the discovery of 'magic angle' graphene has given new inspiration to the formation of heterojunctions. Similarly, the use of hexagonal boron nitride, known as white graphene, as a substrate for graphene devices has more aroused great interest in the graphene/hexagonal boron nitride heterostructure system. Based on the first principles method of density functional theory, the band structure, density of states, Mulliken population, and differential charge density of a tightly packed model of twisted graphene/hexagonal boron nitride/graphene sandwich structure have been studied. Through the establishment of heterostructure models twisted bilayer-graphene inserting hBN with different twisted angles, it was found that the band gap, Mulliken population, and charge density, exhibited specific evolution regulars with the rotation angle of the upper graphene, showing novel electronic properties and realizing metal-insulator phase transition. We find that the particular value of the twist angle at which the metal-insulator phase transition occurs and propose a rotational regulation mechanism with angular periodicity. Our results have guiding significance for the practical application of heterojunction electronic devices.

Transplantation of rat frozen-thawed testicular tissues: Does fragment size matter?

Cryopreservation of testicular tissue from pre-pubertal boys before gonadotoxic treatment is an important step in fertility preservation. Yet, this approach remains experimental, and there is still few study measuring the effect of tissue size on the graft after cryopreservation and transplantation. The objective of this study is to detect the effect of varying tissue sizes on the efficacy of rat testicular tissue cryopreservation and transplantation. Varying sizes of rat testicular tissues were frozen-thawed and autografted. At the 30th day after grafting, the grafts were collected for histology assessment and immunohistochemistry assay for MAGE-A4 (germ cell marker) and CD34 (blood vessel marker). The transplant recovery, seminiferous tubule integrity, tubular diameter, spermatogonia number, and microsvessel density in testicular fragments sizing in 3 mm in length, 3 mm wide, and 3 mm in thickness were significantly lower than other groups. Whereas, the absorption rate of graft sizing in 1 mm in length, 1 mm in wide, and 1 mm in thickness was significantly higher than other groups. Testicular fragment sizing in 2-3 mm in length, 2-3 mm in wide, and 2 mm in thickness (8 mm3-18 mm3) is suitable for rat testicular tissue cryopreservation and transplantation.

Zn(O,S) Buffer Layer for in Situ Hydrothermal Sb2S3 Planar Solar Cells.

Hydrothermal deposition is emerging as a highly potential route for antimony-based solar cells, in which the Sb2(S,Se)3 is typically in situ grown on a common toxic CdS buffer layer. The narrow band gap of CdS causes a considerable absorption in the short-wavelength region and then lowers the current density of the device. Herein, TiO2 is first evaluated as an alternative Cd-free buffer layer for hydrothermally derived Sb2S3 solar cells. But it suffers from a severely inhomogeneous Sb2S3 coverage, which is effectively eliminated by inserting a Zn(O,S) layer. The surface atom of sulfur in Zn(O,S) uniquely provides a chemical bridge to enable the quasi-epitaxial deposition of Sb2S3 thin film, confirming by both morphology and binding energy analysis using DFT. Then the results of the first-principles calculations also show that Zn(O,S)/Sb2S3 has a more stable structure than TiO2/Sb2S3. The resultant perfect Zn(O,S)/Sb2S3 junction, with a suitable band alignment and excellent interface contact, delivers a remarkably enhanced JSC and VOC for Sb2S3 solar cells. The device efficiency with the TiO2/Zn(O,S) buffer layer boosts from 0.54% to 3.70% compared with the counterpart of TiO2, which has a champion efficiency of Cd-free Sb2S3 solar cells with a structure of ITO/TiO2/Zn(O,S)/Sb2S3/Carbon/Ag by in situ hydrothermal deposition. This work provides a guideline for the hydrothermal deposition of antimony-based films upon a nontoxic buffer layer.

Mechanical, Structural and Electronic Properties of CO2 Adsorbed Graphitic Carbon Nitride (g-C3N4) under Biaxial Tensile Strain.

We investigate mechanical, structural and electronic properties of CO2 adsorbed graphitic carbon nitride (g-C3N4) system under biaxial tensile strain via first-principles calculations. The results show that the stress of CO2 adsorbed g-C3N4 system increases and then decreases linearly with the increasing biaxial strain, reaching maximum at 0.12 strain. This is primarily caused by the plane N-C stretching of the g-C3N4. Furthermore, both the Perdew-Burke-Ernzerhof (PBE) and Heyd- Scuseria-Ernzerhof screened hybrid functional (HSE06) band gaps show direct-indirect transitions under biaxial tensile strain and have the maximum also at 0.12 strain. It is found that there is large dipole transition matrix element around Γ point, leading high optical absorption coefficients of the deformed adsorption system, which would be of great use for the applications of new elastic nanoelectronic and optoelectronic devices.

Targeting against the activity of the NLRP3 inflammasome is a potential therapy for rat testicular tissue cryopreservation and transplantation.

The objective of the present experiment was to explore the role of NLRP3 inflammasome in the testicular tissue freezing, thawing and grafting; furthermore, the potential effect of a NLRP3 inhibitor on the function of testis transplant was explored. Tissues from male Wistar rats in pre-pubertal age were cryopreserved, thawed and auto-transplanted into the scrotum treated or not treated with the MCC950 (a NLRP3 inhibitor). After grafting, cryopreserved tissue was removed and analysed. Quantitative morphometric, immunohistochemical techniques and Western blotting were used to evaluate the survival of spermatogonia and the activation of the NLRP3 inflammasome after freezing/thawing/grafting. Moreover, serum IL-1ß level was assessed with ELISA kits. The testicular transplants exhibited upregulated expression of the NLRP3 pathway meditors (NLRP3, IL-1ß). In NLRP3 inhibition group, the rate of recovered grafts, the percentage of intact tubules and spermatogonial number were significantly higher than that in cryopreserved graft group. Moreover, serum concentration of IL-1ß in NLRP3 inhibition group was significantly lower than that in cryopreserved graft group. Testicular tissue cryopreservation and transplantation exhibited upregulated expression of NLRP3 pathway and NLRP3 inflammasome blockade improves testicular graft function. These finding suggest that NLRP3 inflammasome is a therapeutic target for testicular tissue cryopreservation and transplantation.

Testicular damage during cryopreservation and transplantation.

The aim of this study is to do a study of cryoinjury and ischaemic injury on testicular graft during cryopreservation and transplantation. According to time at 1, 3, 7 and 14 days after transplantation, the grafts were collected for immunohistochemistry assay for CD34 (blood vessel marker), VEGF (neoangiogenesis marker), caspase-3 (apoptosis marker) MAGE-A4 (germ cell marker). A significant increase was observed in the density of VEGF-positive blood vessels on day 3, reached a peak on day 7. On post-transplant day 3, a sharp increase occurred in the rate of spermatogonia-expressing caspase-3 until the day 7. At 14th day after transplantation, the spermatogonia number per round tubule of nonfrozen grafts was 41 ± 5.9% from that of fresh control tissues, while, in frozen-thawed grafts, the spermatogonia number per round tubule was 36.8 ± 4.6% from that of fresh control tissues. In testicular grafts, angiogenesis initiated reperfusion from day 3, and the formation of new blood vessel generally is completed about 7 days after transplantation. Angiogenesis in grafts after transplantation plays a crucial role in the restoration of function. Therefore, minimising ischaemic injury as well as improvement of cryopreservation protocols are needed to improve testicular graft after freezing, thawing and grafting.

Study on the effect of municipal solid landfills on groundwater by combining the models of variable leakage rate, leachate concentration, and contaminant solute transport.

The landfill with low economic cost and technical barrier has become a popular option for municipal solid waste treatment, but it is likely to seriously pollute groundwater by solute leaching. In this study, the pollutants concentration model, leakage rate model, and the solute transport model were coupled to investigate the effect of municipal solid waste landfill on groundwater quality. Major results obtained are, (1) the leakage rate of leachate differs significantly among the landfilling stage, covering stage and completely covered stage as the leachate depth varies with the infiltration rainfall. The contact condition between HDPE and CCL was found to be a key factor in determining the leakage rate of leachate. Ensuring good connection between HPDE and CCL is thus critical in protecting groundwater from being polluted by landfill. (2) The NH3-N as a proxy for organic pollutants was generated via the degradation process, and Cl- as a proxy for inorganic pollutants is a leachable fraction of mobilized substances. The concentration of Cl- is higher than that of NH3-N before 7600 days, then the concentration of NH3-N becomes roughly stable while that of Cl- continues to decrease. (3) The load of NH3-N as a proxy for organic pollutants declines linearly downwards before the completely covering stage. The load of Cl- as a proxy for inorganic pollutants increased during the first five years, and then declined. (4) In the case study, the path of maximum pollutants concentration is perpendicular to the groundwater contour, and the maximum pollutants concentration has two peaks, occurring on 7106 days and 11,554 days, respectively. The change laws of maximum pollutants concentration are similar for different connections between HPDE and CCL.

Theoretical perspective on the electronic structure and optoelectronic properties of type-II SiC/CrS2van der Waals heterostructure with high carrier mobilities.

Two-dimensional heterostructures formed by stacking layered materials play a significant role in condensed matter physics and materials science due to their potential applications in high-efficiency nanoelectronic and optoelectronic devices. In this paper, the structural, electronic, and optical properties of SiC/CrS2van der Waals heterostructure (vdWHs) have been investigated by means of density functional theory calculations. It is confirmed that the SiC/CrS2vdWHs is energetically and thermodynamically stable indicating its great promise for experimental realization. We find that the SiC/CrS2vdWHs has a direct-band gap and type-II (staggered) band alignment, which can effectively separate the photo-induced electrons and holes pairs and extend their life time. The carrier mobilities of electrons and holes along the armchair and zigzag directions are as high as 6.621 × 103and 6.182 × 104 cm2 V-1 s-1, respectively. Besides, the charge difference and potential drop across the interface can induce a large built-in electric field across the heterojunction, which will further hinder the electron and hole recombination. The SiC/CrS2vdWHs has enhanced optical absorption capability compared to individual monolayers. This study demonstrates that the SiC/CrS2vdWHs is a good candidate for application in the nanoelectronic and optoelectronic devices.

One- and two-dimensional electrical contacts and transport properties in monolayer black phosphorene-Ni interface.

Contacts between black phosphorene (BP) and metal electrodes are critical components of BP-based devices and can dramatically affect device performance. In this paper, we adopted first-principles calculations to explore binding energies, electronic structures, spatial potential distribution of monolayer BP-Ni interfaces in surface contact and edge contact types, and used density functional theoretical coupled with nonequilibrium Green's function method to investigate the electrical transport properties for transport systems of monolayer BP with Ni electrodes. Our calculated results indicate that contact type between monolayer BP and metal Ni electrodes may much affect the transport properties of monolayer BP-Ni devices. Interfacial interaction between Ni and monolayer BP in edge contact type is stronger than that in surface contact type. The potential distributions indicate that edge contact type is more beneficial for reducing contact resistance of monolayer BP-Ni contacts and conducive to improve the performance of BP-Ni electrode device.

Equibiaxial Strained Oxygen Adsorption on Pristine Graphene, Nitrogen/Boron Doped Graphene, and Defected Graphene.

We report first-principles calculations on the structural, mechanical, and electronic properties of O2 molecule adsorption on different graphenes (including pristine graphene (G-O2), N(nitrogen)/B(boron)-doped graphene (G-N/B-O2), and defective graphene (G-D-O2)) under equibiaxial strain. Our calculation results reveal that G-D-O2 possesses the highest binding energy, indicating that it owns the highest stability. Moreover, the stabilities of the four structures are enhanced enormously by the compressive strain larger than 2%. In addition, the band gaps of G-O2 and G-D-O2 exhibit direct and indirect transitions. Our work aims to control the graphene-based structure and electronic properties via strain engineering, which will provide implications for the application of new elastic semiconductor devices.