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The charge carrier transport mechanism of passivating contacts which feature an ultra-thin oxide layer is investigated by studying temperature-dependent current-voltage characteristics. 4-Terminal dark J-V measurements at low temperatures reveal non-linear J-V characteristics of passivating contacts with a homogeneously grown silicon oxide, which result in an exponential increase in contact resistance towards lower temperature. The attempt to describe the R(T) characteristic solely by thermionic emission of charge carriers across an energy barrier leads to a significant underestimation of the resistance by several orders of magnitude. However, the data can be described properly with the metal-insulator-semiconductor (MIS) theory if tunneling of charge carriers through the silicon oxide layer is taken into account. Furthermore, temperature-dependent light J-V characteristics of solar cells featuring passivating contacts at the rear revealed a FF drop at T < 205 K, which is near the onset temperature of the exponential increase in contact resistivity. [ABSTRACT FROM AUTHOR]

Decay and propagation properties of symmetric surface plasmon polariton (SPP) mode based on metal–insulator–metal (MIM) waveguide are investigated numerically. SPP mode is excited through a dipole embedded in Al 2 O 3 layer of Au / Al 2 O 3 / Au structure. We demonstrate that the distance between the dipole and Al 2 O 3 / Au interface is an important tunable parameter to influence the decay properties. The electric/magnetic field intensity horizontal and vertical decay lengths of symmetric SPP mode are 19 nm and 24 nm, respectively. Moreover, the propagation length along Al 2 O 3 / Au interface of symmetric SPP mode depends on Al 2 O 3 layer thickness. The maximal propagation length reaches 0.608 μ m with Al 2 O 3 layer thickness of 100 nm. These values can provide a theoretical reference for designing a high-performance SPP source using Au / Al 2 O 3 / Au structure. [ABSTRACT FROM AUTHOR]

We study the properties of the InSb (001) surface covered with ultrathin KBr films, with a thickness of 1–4 ML. KBr deposition does not strongly perturb the crystallographic structure of the InSb surface and the electronic structure of the substrate also remains unaffected by the overlayer. A simple model of the studied system is proposed, in which a thin KBr layer is treated as a dielectric film, modifying potential barrier for the electrons tunneling to/from the InSb substrate. Apparent step heights on the KBr film, measured using scanning tunneling microscope (STM), agree well with the predictions of the model and the atomically-resolved STM images show the structure of the InSb-KBr interface. Our results demonstrate that STM may be used as a tool for investigations of the semiconductor–insulator interfaces. [ABSTRACT FROM AUTHOR]

The electronic properties of hexagonal boron nitride ( h -BN) are controllable by applying normal pressure. In this work, we perform first-principles density functional calculation to investigate electronic structure of several h -BN bilayers with different stacking patterns under normal pressure. The results suggest that the band gap of h -BN bilayer, surprisingly, undergoes both decreasing and increasing trend with increasing of normal pressure, which is considerably different from monotonously decreasing by applying electric field. Furthermore, it is found that the transformation from a direct- to an indirect-gap can be achieved in the case of stacking pattern II as the pressure above 34.3%. However, the insulator-semiconductor transition can be induced for stacking pattern I and III under similar normal pressure. The studies indicate a unique yet easy pathway to tune the electronic properties of h -BN by normal pressure, which may pave the way for their potential applications as optoelectronic device materials. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effect of yttrium content on the structural properties and sensing characteristics of YbY x O y sensing membranes for electrolyte–insulator–semiconductor (EIS) sensors to detect the rheumatoid factor (RF). The YbY x O y EIS device prepared at the 60 W plasma condition exhibited a higher sensitivity of 65.77 mV/pH, a lower hysteresis voltage of ∼1 mV, and a smaller drift rate of 0.14 mV/h than did those prepared at the other conditions. We attribute this behavior to the optimal yttrium content in the YbY x O y film forming a smooth surface. Furthermore, we used a novel YbTi x O y EIS biosensor to measure the RF antigen in human serum because of its rapid and label-free detection. Two different techniques were used for the immobilization of RF antibody onto the surface of an YbTi x O y EIS sensor. The RF antibody was directly immobilized on the EIS surface modified with 3-aminopropyltriethoxysilane (APTES) followed by glutaraldehyde (GA). In contrast, a mixture of 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) solution was used to functionalize the carboxyl groups at the tail of RF antibodies. RF antibodies functionalized with the active NHS esters were covalently immobilized on the APTES-modified YbTi x O y surface. The immobilized RF antibodies on the EIS that are functionalized with the EDC and NHS exhibit higher (41.11 mV/pC RF ) for detection of serum RF antigen in the range 10 −7 to 10 −3 M, compared to traditional antibody immobilization technique via APTES and GA linkage. The YbTi x O y EIS biosensor is a promising analytical tool for RF antigen monitoring due to its good sensitivity, stability and repeatability. [ABSTRACT FROM AUTHOR]

The quality of the interface between silicon and a dielectric is one of the main influencing parameters for crystalline silicon surface passivation. In this work, this interface is examined by means of capacitance voltage (CV) and nuclear resonance reaction analysis (NRRA) measurements for SiN x :H as well as SiO 2 capped SiN x :H passivated p-type float zone silicon samples. Due to a highly sensitive NRRA measurement setup, very small differences in hydrogen concentration at the interface could be detected for the first time and a significant correlation between hydrogen concentration, interface state trap densities D it and passivation quality is found. The results of this study present easily implementable processes to improve the quality of SiN x :H surface passivation and process stability for solar cell and module production applications. First optimised industrial type Al-BSF p-type cells feature 2 mV and 0.5 mA/cm 2 gains in V oc and j sc , leading to efficiencies of up to 19.1%. [ABSTRACT FROM AUTHOR]

Abstract: A CeO2-based multi-analyte electrolyte–insulator–semiconductor (EIS) biosensor has been fabricated on silicon substrate. To enhance the material quality and sensing performance, annealing treatment in N2 and O2 ambient has been incorporated. To examine the annealing effects, material analyses were conducted using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) to identify optimal treatment conditions. Furthermore, sensing performance for various ions of Na+, K+, urea, and glucose has also been tested. Results indicate that the membrane annealed at 800°C in O2 ambience exhibited a better performance with higher multianalyte sensitivity and a lower drift rate compared with the membrane annealed in N2 ambience. Oxygen in O2 ambience may cause stronger reflow and fill in the oxygen vacancy so that the material properties and sensing capability can be improved in O2 annealing ambience. [Copyright &y& Elsevier]

Highlights: [•] Cell growth and metabolism were continuously and synchronously monitored by cellular impedance sensing and LAPS based on the same sensor structure. [•] Electrolyte-insulator-semiconductor (EIS) structure was used as the sensor structure. [•] Equivalent circuit model for cellular impedance sensing was build. [•] Cytotoxicity of heavy metal Cadmium (Cd) was evaluated. [Copyright &y& Elsevier]

Abstract: This work presents a novel insight to the aspects of silicon surface passivation and the influence of thin intermediate layers generated by chemically grown silicon oxides. Strong light induced effects on passivation properties are investigated. After exposure to light (0.25 suns) for about 60 s, samples based on a PECVD layer system consisting of SiNx and SiO2 deposited on crystalline silicon with native silicon oxides show an improvement of more than 100% in minority carrier lifetime. These improvements are stable over months and lead to effective surface recombination velocities as low as 10cm/s on chemically polished p-type FZ wafers. With the use of different light sources, corona charging and annealing experiments the effect is investigated in detail. Finally, the effect is proposed to be a photo induced curing process of defects in the Si/SiO2 interface with the incorporation of hydrogen. [Copyright &y& Elsevier]

Metal-induced crystallization has allowed for high-quality Si and Ge thin films on insulators at low temperatures; however, there has been difficulty for SiGe alloys of intermediate compositions. Here we demonstrate a large-grained (> 100 μm), 99% (111)-oriented Si 0.4 Ge 0.6 layer on a glass substrate through layer exchange between Al and amorphous Si 0.4 Ge 0.6 layers. Slow annealing below 350 °C is a key to suppressing nucleation and facilitating lateral growth. The use of the (111)-oriented SiGe layers as epitaxial templates will pave the way for integrating various materials monolithically on three-dimensional Si large-scale integrated circuits and on multi-functional displays. [ABSTRACT FROM AUTHOR]