EFFECTS OF DEEP CENTERS AT PT SI INTERFACES AND HYDROGENATION

Electrical measurements were combined with surface techniques to study the Pt/Si interfaces at various silicide formation temperatures. Effects of deep centers on the Schottky barrier heights were studied. Hydrogen plasma treatment was used to passivate the impurity/defect centers at the interfaces, and the effects of hydrogenation on the Schottky barrier heights were also examined. Combining our previous study on the Pt/Si interfacial reaction, factors influencing the PtSi/Si Schottky barrier diode are discussed.

PHOTOLUMINESCENCE STUDY OF GAAS/ALGAAS QUANTUM-WELL HETEROSTRUCTURE INTERFACES

Photoluminescence (PL) is used to study the interface properties of GaAs/AlGaAs quantum well (QW) heterostructures prepared by molecular beam epitaxy with growth interruption (GI). The discrete luminescence lines observed for the sample with GI are assigned to the splitting of the heavy-hole exciton associated with heterointerface islands with the lateral size greater than exciton diameter and mean height less than one monolayer, and the spectra have the Gaussian lineshapes. The results strongly support the microroughness model. We also study the temperature dependence of the exciton energies and find that excitons are localized at the interface roughness at low temperature even in the sample with GI. The lateral size of the microroughness of the GI sample is estimated to be less than 5 nm from the exciton localization energy.

DIFFERENT INTERDIFFUSION CHARACTERISTICS BETWEEN AG/YBA2CU3O7-X AND AL/YBA2CU3O7-X CONTACT INTERFACES

The differences between the interdiffusion characteristics of Ag/YBa2Cu3O7-x and Al/YBa2Cu3O7-x contact interfaces have been revealed by secondary ion mass spectrometry (SIMS). The different electrical properties of Ag/YBa2Cu3O7-x and YBa2Cu3O7-x films after high temperature treatment are well understood by the SIMS results.

Investigation of GaAs/AlGaAs interfaces by reflectance-difference spectroscopy

The in-plane optical anisotropy of several GaAs/AlGaAs quantum well samples with different well widths has been measured at room temperature by reflectance-difference spectroscopy (RDS). The RDS line shapes are found to be similar in all the samples examined here, which dominantly consist of two peak-like signals corresponding to 1HH-->1E and 1LH-->1E transition. As the well width is decreased, or the 1 ML InAs layer is inserted at one interface, the intensity of the anisotropy increases quickly. Our detail analysis shows that the anisotropy mainly arises from the anisotropic interface roughness. The results demonstrate that the RDS technique is sensitive to the interface structures.

Ionic liquids Supported Growth of Highly Ordered Microdroplets Induced by Fluidic Leakage at Poly(dimethylsiloxane) Interfaces

"Fluidic leakage" caused by vacuum force at the reversible sealing poly(dimethylsiloxane) (PDMS) interfaces was converted to one useable avenue, which led to formation of highly ordered surfactant microdroplets functionalized with ionic liquids (ILs). Vacuum force is the prerequisite to lead constant microsolutions to diffuse to the PDMS interfaces. Imidazolium ions of ILs rendered structural rearrangement of the surfactant aggregates and the ordered droplets formation.

Directing single-walled carbon nanotubes to self-assemble at water/oil interfaces and facilitate electron transfer

Both the behavior and the general key factors for assembling flexible SWNT films at the water/oil interface were investigated; the electron transfer, one of the most fundamental chemical processes, at the SWNT-sandwiched water/oil interface was also firstly illustrated using scanning electrochemical microscopy.

Electronic structure of interfaces between copper-hexadecafluoro-phthalocyanine and 2,5-bis(4-biphenylyl) bithiophene

The interfaces formed between copper-hexadecafluoro-phthalocyanine (F16CuPc) and 2,5-bis(4-biphenylyl) bithiophene (BP2T) were examined using photoemission and inverse photoemission spectroscopy. It is observed that in F16CuPc/BP2T the heterojunction is characterized by band bending in both materials, while in BP2T/F16CuPc the band bending is confined in BP2T only. The combination of the band bending and finite Debye lengths provides an explanation to the observed ambipolar behavior of the organic thin film transistors based on such heterojunctions.

Systematic investigation of alkali metal ion transfer across the micro- and nano-water/1,2-dichloroethane interfaces facilitated by dibenzo-18-crown-6

Facilitated alkali metal ion (M+= Li+, Na+, K+, Rb+, and Cs+) transfers across the micro- and nano-water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nanopipets by dibenzo-18-crown-6 (DB18C6) have been investigated systematically using cyclic voltammetry. The theory developed by Matsuda et al. was applied to estimate the association constants of DB18C6 and M+ in the DCE phase based on the experimental voltammetric results. The kinetic measurements for alkali metal ion transfer across the W/DCE interface facilitated by DB18C6 were conducted using nanopipets or-submicropipets, and the standard rate constants (k(0)) were evaluated by analysis of the experimental voltammetric data. They increase in the following order: k(Cs+)(0) < k(Li+)(0) < k(Rb+)(0) < k(Na+)(0) < k(K+)(0), which is in accordance with their association constants except Cs+ and Li+.

IMPEDANCE STUDY OF THE INTERFACES BETWEEN LITHIUM, POLYANILINE, LITHIUM-DOPED MNO2 AND MODIFIED POLY(ETHYLENE OXIDE) ELECTROLYTE

Impedance study was carried out for the interfaces between lithium, polyaniline (PAn), lithium-doped MnO2 and modified poly(ethylene oxide) (PEO) electrolyte under various' conditions. The interfacial charge-transfer resistances R(ct) on PEO/PAn, R(ct) on PEO/LiMn2O4 increase with depth-of-discharge and decrease after the charge of the cell containing modified PEO as electrolyte. The charge-transfer resistance R(ct) on PEO/PAn is higher than R(ct) on PEO/LiMn2O4 under the same condition, since inserted species and mechanism are different for both cases. In the case of PAn, an additional charge-transfer resistance might be related to the electronic conductivity change in discharge/charge potential range, as it was evident from a voltammetry curve. With increasing cycle numbers, the charge-transfer resistance increases gradually. The impedance results also have shown that at low frequency the diffusion control is dominant in the process of the charge and discharge of Li/PEO/PAn or Li/PEO/LiMn2O4 cell. The diffusion coefficients have been calculated from impedance data.