Leakage Mechanism and Cycling Behavior of Ferroelectric Al0.7Sc0.3N.

Ferroelectric scandium-doped aluminum nitride (Al1-xScxN) is of considerable research interest because of its superior ferroelectricity. Studies indicate that Al1-xScxN may suffer from a high leakage current, which can hinder further thickness scaling and long-term reliability. In this work, we systematically investigate the origin of the leakage current in Al0.7Sc0.3N films via experiments and theoretical calculations. The results reveal that the leakage may originate from the nitrogen vacancies with positively charged states and fits well with the trap-assisted Poole-Frenkel (P-F) emission. Moreover, we examine the cycling behavior of ferroelectric Al0.7Sc0.3N-based FeRAM devices. We observe that the leakage current substantially increases when the device undergoes bipolar cycling with a pulse amplitude larger than the coercive electric field. Our analysis shows that the increased leakage current in bipolar cycling is caused by the monotonously reduced trap energy level by monitoring the direct current (DC) leakage under different temperatures and the P-F emission fitting.

Demonstration of 10 nm Ferroelectric Al0.7Sc0.3N-Based Capacitors for Enabling Selector-Free Memory Array.

In this work, 10 nm scandium-doped aluminum nitride (AlScN) capacitors are demonstrated for the construction of the selector-free memory array application. The 10 nm Al0.7Sc0.3N film deposited on an 8-inch silicon wafer with sputtering technology exhibits a large remnant polarization exceeding 100 µC/cm2 and a tight distribution of the coercive field, which is characterized by the positive-up-negative-down (PUND) method. As a result, the devices with lateral dimension of only 1.5 µm show a large memory window of over 250% and a low power consumption of ~40 pJ while maintaining a low disturbance rate of <2%. Additionally, the devices demonstrate stable multistate memory characteristics with a dedicated operation scheme. The back-end-of-line (BEOL)-compatible fabrication process, along with all these device performances, shows the potential of AlScN-based capacitors for the implementation of the high-density selector-free memory array.

Bis(ethanamidinium) (1,10-phen-an-thro-line-2,9-dicarboxyl-ato)manganate(II) hepta-hydrate.

In the title complex, (C2H7N2)2[Mn(C14H6N2O4)2]·7H2O, the Mn(II) atom is coordinated by four N atoms and four O atoms from two 1,10-phenanthroline-2,9-dicarboxyl-ate ligands in a distorted dodeca-hedral geometry. The double negative charge is balanced by two ethanamidinium cations. A three-dimensional supra-molecular structure is formed through N-H⋯O and O-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distance = 3.553 (2) Å].

Diaqua-bis-(5-carb-oxy-2-ethyl-1H-imidazole-4-carboxyl-ato-κ(2)N(3),O(4))cobalt(II) trihydrate.

In the title compound, [Co(C(7)H(7)N(2)O(4))(2)(H(2)O)(2)]·3H(2)O, the Co(II) cation, located on an inversion center, is N,O-chelated by two 5-carboxy-2-ethyl-1H-imidazole-4-carboxylate anions and further coordinated by two water mol-ecules in a distorted octa-hedral geometry. Only one carboxy group of the anion is deprotonated, and the two carboxyl groups of the same anion are linked via an intra-molecular O-H⋯O hydrogen bond. One of the lattice water mol-ecules is located on an inversion center, its H atom equally disordered over two positions. One of H atoms of another lattice water mol-ecules is also equally disordered over two sites. Water H atoms and the amino H atom all are involved in an inter-molecular hydrogen-bonded network in the crystal.

cis-Tetra-aqua-bis-{5-[4-(1H-imidazol-1-yl-κN(3))phen-yl]tetra-zolido}manganese(II) dihydrate.

In the title compound, [Mn(C(10)H(7)N(6))(2)(H(2)O)(4)]·2H(2)O, the Mn(2+) lies on a twofold rotation axis and is six-coordinated by two N atoms from the cis-related monodentate 5-[4-(imidazol-1-yl)phen-yl]tetra-zolide ligands and four O atoms from the coordinated water mol-ecules. The complex mol-ecules are connected via water O-H⋯O and O-H⋯N hydrogen bonds and weak π-π stacking inter-actions between the benzene rings [minimum ring centroid separation = 3.750 (6) Å] into a three-dimensional polymeric structure. The imidazolyl group of the ligand is partially disordered over two sets of sites with refined occupancies of 0.531 (7):0.469 (7).

Tetra-aqua-bis-[4-(1H-imidazol-1-yl-κN(3))benzoato]cobalt(II).

In the title compound, [Co(C(10)H(7)N(2)O(2))(2)(H(2)O)(4)], the Co(II) atom lies on an inversion centre and displays a slightly distorted octa-hedral geometry. The coordination sphere is defined by two mutually trans N atoms from two 4-(imidazol-1-yl)benzoate ligands and the O atoms from four water mol-ecules. The crystal structure is stabilized by O-H⋯O hydrogen bonds.

catena-Poly[(diaqua-strontium)-bis-{µ-5-[4-(1H-imidazol-1-yl)phen-yl]tetra-zolido}].

In the title complex polymer, [Sr(C(10)H(7)N(6))(2)(H(2)O)(2)](n), the Sr(II) atom lies on an inversion centre and is coordinated by four N atoms from two bidentate bridging trans-related 5-[4-(1H-imidazol-1-yl)phen-yl]tetra-zolide ligands [Sr-N = 2.387 (4) Šfor the tetrazolide moiety and Sr-N = 2.273 (5) Šfor the imidazole moiety], and by two O atoms from water mol-ecules [Sr-O = 2.464 (4) Å], giving a distorted octa-hedral coordination. Pairs of ligand bridges link the complex units, forming chains which extend along [111] and are inter-associated through O(water)-H⋯N hydrogen bonds, giving a two-dimensional network structure parallel to (001). Weak π-π stacking inter-actions between the benzene and imidazole rings are also present [minimum ring centroid separation = 3.691 (4) Å].

catena-Poly[(trans-diaqua-cadmium)-bis-{µ-5-[4-(1H-imidazol-1-yl)phen-yl]tetra-zol-1-ido}].

In the title compound, [Cd(C(10)H(7)N(6))(2)(H(2)O)(2)], the Cd(II) atom lies on an inversion centre and is coordinated by four N atoms from 5-[4-(1H-imidazol-1-yl)phen-yl]tetra-zol-1-ide ligands and two O atoms from the coordinated water mol-ecules in an octa-hedral arrangement. The complex polymeric chains are inter-connected via inter-molecular water O-H⋯N hydrogen bonds into a three-dimensional network.

5-[4-(1H-Imidazol-1-yl)phen-yl]-1H-tetra-zole.

In the title compound, C(10)H(8)N(6), the tetra-zole and benzene rings are close to being coplanar [dihedral angle = 9.90 (16)°], but the imidazole ring is rotated 37.18 (09)° out of the benzene plane. In the crystal, mol-ecules are connected through tetra-zole-imidazole N-H⋯N hydrogen bonds, giving rise to zigzag chains, which extend along [010].

5H-Imidazo[4,5-f][1,10]phenanthroline.

The title mol-ecule, C(13)H(8)N(4), is is essentially planar [r.m.s. deviation for all non-H atoms = 0.025 (3) Å]. In the crystal, mol-ecules are connected through one weak bifurcated N-H⋯(N,N) hydrogen bond and three π-π stacking inter-actions between pyridine and imidazole rings [centroid-centroid distance = 3.631 (8) Å] and between pyridine and benzene rings [centroid-centroid distances = 3.675 (5) and 3.666 (2) Å].

[Emulsion liquid membrane extraction with D2EHPA mobile carrier Hirudinaria manillensis hirudin in experimental study].

OBJECTIVE: To study the extraction system of hirudin emulsion liquid membrane with the Poecilobdella manillensis as raw material, di-(2-ethylhexyl) phosphate (D2EHPA) as carrier, Span 80 as emulsifier, octane and D2EHPA mixed to constitute membrane solution, diluted HCl solutions as internal aqueous phase. METHOD: Using the orthogonal experiment to optimize the extraction conditions of hirudin reference substance such as membrane phase, internal aqueous phase volume ratio (MIPVR), external aqueous phase pH, internal aqueous phase pH, mobile carrier concentration and so on, and then using hirudin crude extracts to do purifying experiment, and gaining experimental samples. RESULT: The optimal conditions of hirudin extraction were as follows: MIPVR 10: 3, internal aqueous phase pH 2.6, external aqueous phase pH 3.4, the mass fraction of carrier D2EHPA 2%. In the optimal extraction conditions, when the initial concentration of hirudin was one anti-thrombin activity units (ATU) x mL(-1), ATU recovery rate of the reference substance was 83.06%. In the purifying experiment of crude extracts, ATU recovery rate was 82.99%, and the specific activity of sample was 3 289.48 the ATU x mg(-1). Discontinuous polyacrylamide gel electrophoresis and spectral scanning, the results showed that the purity and reference substance were considerable. CONCLUSION: The method of preparation hirudin was relatively simple, the purity of the experimental samples and ATU recovery were both high.

Hierarchical porous mussel shells as soil amendment for oil spill remediation.

In this work, a new type of micromesoporous substance was prepared with fatty alcohol-polyoxyethylene ether (AEO) surfactant freezing penetration and pyrolysis using shells as raw materials. The obtained material exhibited good adsorbability and could be added to oil-contaminated soil to adsorb the pollutant, which resulted in the regeneration of the initially polluted soil. It was determined that the main component of the developed substance was CaCO3. Importantly, the conducted experiments revealed that the obtained mussel micromesoporous material displayed certain adsorption effects toward petroleum hydrocarbons in a diesel solution. Moreover, it was found that chemical adsorption was more optimal than physical adsorption. The soil remediation effect was the best when the content of the mussel micromesoporous material in the soil was 400 g/kg. Under these conditions, the removal rate of petroleum hydrocarbon was established at 49.38%. This study indicated that micromesoporous material has great potential in the application of oil contaminated soil remediation.

Magnetic properties and phase change features in Fe-doped Ge-Sb-Te.

The relationship between magnetic property and phase change features in Fe-doped Ge-Sb-Te has been studied. Fe-doped Ge-Sb-Te is a phase change magnetic material, which exhibits a fast phase change feature and different magnetic, optical and electrical properties between amorphous and crystalline states. However, the crystallization temperature increases and crystallization rate drops with an increase of Fe doping content. Fe doping content should be less than the solid solubility limit so that Fe-doped Ge-Sb-Te has both magnetic property and phase change features. Fe-doped Ge-Sb-Te at crystalline state shows p-type conduction and has a high hole concentration. The Ruderman-Kittel-Kasuya-Yosida indirect interaction via carriers is the origin of the ferromagnetism in Fe-doped Ge-Sb-Te.

catena-Poly[hexaaquamagnesium(II) [bis(µ3-5-nitro-2-oxidoisophthalato)dicopper(II)] dihydrate].

In the centrosymmetric dinuclear anions of the title bimetallic complex, {[Mg(H(2)O)(6)][Cu(2)(C(8)H(2)NO(7))(2)]·2H(2)O}(n), each Cu(II) ion is strongly coordinated by four O atoms in a distorted square-planar geometry. Two of these O atoms belong to phenolate groups and the other two to carboxylate groups from 5-nitro-2-oxidoisophthalate (L1) trianions, derived from 5-nitrobenzene-1,2,3-tricarboxylic acid (O(2)N-H(3)L). The phenolate O atoms bridge the two Cu(II) ions in the anion. In addition, each Cu(II) cation interacts weakly with a symmetry-related carboxylate O atom of an adjacent L1 ligand, giving a square-pyramidal coordination geometry. The copper residue forms a ladder-like linear coordination polymer via L1 ligands. The [Mg(H(2)O)(6)](2+) cations sit on centres of inversion. The polymeric anions, cations and free water molecules are self-assembled into a three-dimensional supramolecular network via O-H···O hydrogen bonds.

Bis(2,4-dichloro-phen-oxy-acetato-κO,O)(5,5'-dimethyl-2,2'-bipyridine-κN,N')cobalt(II).

In the title compound, [Co(C(8)H(5)Cl(2)O(3))(C(12)H(12)N(2))], the Co(II) atom, lying on a twofold rotation axis, is coordinated by four O atoms from two chelating 2,4-dichloro-phen-oxy-acetate ligands and two N atoms from a 5,5'-dimethyl-2,2'-bipyridine ligand, displaying a distorted octa-hedral geometry. A three-dimensional supra-molecular structure is formed through inter-molecular C-H⋯O hydrogen bonds and π-π stacking inter-actions between the pyridine and benzene rings [centroid-centroid distance = 3.779 (2) Å].

(5,5'-Dimethyl-2,2'-bipyridine-κN,N')(1-naphthyl-acetato-κO)(1-naphthyl-acetato-κO,O')zinc hemihydrate.

In the title compound, [Zn(C(12)H(9)O(2))(2)(C(12)H(12)N(2))]·0.5H(2)O, the water mol-ecule lies on a twofold rotation axis. The Zn(II) atom is coordinated by three O atoms from two 1-naphthyl-acetate ligands, one monodentate and the other asymmetric bidentate chelate, and two N atoms from a 5,5'-dimethyl-2,2'-bipyridine ligand, giving an irregular environment. In the crystal, the complex mol-ecules are inter-linked through the water mol-ecule by O-H⋯O(carboxyl-ate) hydrogen bonds, together with weak C-H⋯O and bipyridine ring π-π stacking inter-actions [ring centroid separation = 3.761 (2) Å], giving a two-dimensional network structure.

Poly[[[diaqua-sodium]-µ(3)-5-carb-oxy-2-ethyl-1H-imidazole-4-carboxyl-ato-κN,O:O:O] monohydrate].

In the title complex, {[Na(C(7)H(7)N(2)O(4))(H(2)O)(2)]·H(2)O}(n), the Na(I) atom exhibits a distorted octa-hedral geometry and is six-coordinated in an NO(5) environment. The equatorial plane is defined by three O atoms and one N atom from two distinct 5-carb-oxy-2-ethyl-1H-imidazole-4-carboxyl-ate (H(2)EIDC) ligands and one coordinated water mol-ecule, and the apical sites are occupied by one carboxyl O atom from one H(2)EIDC ligand and one O atom from the other coordinated water mol-ecule. The Na(I) atoms are linked by H(2)EIDC ligands, generating an infinite double chain along the a axis. These chains are further connected via O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional supra-molecular network.

2-Ethyl-1H-imidazole-4-carboxyl-ate monohydrate.

In the title compound, C(7)H(8)N(2)O(4)·H(2)O, the imidazole N atom is protonated and one of the carboxyl-ate groups is deprontonated, forming a zwitterion. The two carboxyl groups are are approximately coplanar with the imidazole ring [O-C-C-C torsion angles = -176.8 (2) and 2.9 (4)° for one group and -4.6 (3) and 176.4 (2)° for the other] and have an intra-molecular O-H⋯O hydrogen bond between them. The water mol-ecule is linked to the organic mol-ecules via an N-H⋯O hydrogen bonds. Inter-molecular O-H⋯O and N-H⋯O hydrogen bonds are found in the crystal structure.

3-Carb-oxy-5-(pyridinium-4-yl)benzoate: a redetermination.

The title compound, C(13)H(9)NO(4), crystallizes in a zwitterionic form with the pyridine N atom protonated and the carboxyl OH group deprotonated. The benzene and pyridinium rings are inclined with a dihedral angle of 31.42 (14)° between them. A previous report of this stucture claims, we believe incorrectly, that neither of the carboxyl-ate groups is deprotonated [Zhang et al. (2010 ▶). Acta Cryst. E66, o2928-o2928]. In the crystal, inter-molecular O-H⋯O, N-H⋯O and weak C-H⋯O hydrogen-bonding inter-actions link adjacent mol-ecules into a three-dimensional supra-molecular network.

catena-Poly[[diaqua-strontium]-bis-(µ-quinoline-3-carboxyl-ato)].

The title compound, [Sr(C(10)H(6)NO(2))(2)(H(2)O)(2)](n), contains an eight-coordinate Sr(II) ion displaying a distorted square-anti-prismatic geometry, two quinoline-3-carboxyl-ate ligands and two terminal water mol-ecules. The Sr(II) atom is surrounded by six carboxyl-ate O atoms from four separate quinoline-3-carboxyl-ate ligands and two O atoms from two coordinated water mol-ecules. The bridging carboxyl-ate O atoms [Sr-O = 2.498 (3) and 2.495 (3) Å] link Sr(II) atoms, forming a chain substructure extending along the c axis. The chains are linked by O-H⋯N and O-H⋯O hydrogen bonds, giving a three-dimensional framework structure.