二合一芯片

由于整合开关器件与反并联二极管这一概念具有难以攻克的技术挑战,因此近年来这一技术仅被用于低功率组件（如IGBT和MOSFET）以及特殊应用。另外,IGCT等大面积双极型器件已经采用了单片集成技术,但其中的IGCT和二：极管需要完全分离的硅区。     

Deposition and structure characterization of carbon films prepared at atmospheric pressure by plasma jet

Amorphous carbon films were deposited on stainless steel substrates by plasma jet chemical vapor deposition (PJCVD). The carbon coatings have been prepared at atmospheric pressure in an argon/acetylene mixture. The Ar/C₂H₂ gas volume ratio varied from 100:1 to 200:1, while the distance between the plasma torch nozzle exit and the samples was 0.005–0.02 m. Scanning electron microscope analysis demonstrated that the surface roughness and growth rate of the coatings increase with the decrease of the Ar/C₂H₂ ratio. The ERDA results showed that the hydrogen concentration rises from 5 at.% to 27 at.% with the increase of the distance from 0.005 to 0.02 m. The increase of the Ar/C₂H₂ ratio from 100:1 to 200:1 slightly increases the hydrogen and oxygen concentration in the films. The Raman spectroscopy results indicated that the sp³ C–C carbon sites are replaced by sp³ CH_2–3 bonds with the increase of the deposition distance. The microhardness of the carbon films deposited at 0.005 m was in range of 7.1–9.3 GPa.     

A new method for immunosensor preparation: Atmospheric plasma torch

This paper describes a new method for the modification of piezoelectric quartz crystals for immunosensor preparation. The surfaces of the piezoelectric quartz crystals were modified employing Atmospheric Pressure Plasma System using different monomers such as Ethylene diamine (EDA), 1,4-Diaminobutane (DAB) and n-Butylamine (BA). The atmospheric pressure plasma system was adjusted to use the temperature sensitive and volatile monomers. A tunnel from stainless steel was constructed and combined with the plasma torch to introduce the monomers into the plasma jet and preventing the mixing of atmospheric air with the plasma jet. Plasma parameters were; power: 1 kW, pressure: 1 atm, speed of plasma particles: 219 m/s, and exposure time 10 min for EDA and BA monomers, 15 min for DAB monomer. Crystals were characterized by frequency shift measurements, Atomic Force Microscopy (AFM) imaging, contact angle measurements and Infrared (IR) spectra. Frequency shifts for EDA, DAB and BA modified crystals after plasma modification were 56 ± 10, 143 ± 3 and 904 ± 3 Hz respectively. AFM images showed the presence of a film on the surfaces for all monomers. N-H, C-N, C-H and CO group bands were determined in the IR spectra of the crystals. Decrease in the contact angle values of the modified crystals indicated the increase in hydrophilicity. Those results showed that amine containing films on the crystal surfaces were successfully deposited using atmospheric pressure plasma torch. The chemical groups on quartz surface were further activated with gluteraldehyde (GA) and protein immobilisation properties were checked with test antibody (anti-aflatoxin B1) in liquid phase quartz crystal microbalance system. The dip coating method was chosen for immobilisation procedure. After the immobilisation step, chemical structure of surfaces was analyzed by X-ray Photoelectron Spectroscopy.     

Optical and electrical characterization of (Ga,Mn)N/InGaN multiquantum well light-emitting diodes

(Ga,Mn)/N/InGaN multiquantum well (MQW) diodes were grown by molecular beam epitaxy (MBE). The current-voltage characteristics of the diodes show the presence of a parasitic junction between the (Ga,Mn)N and the n-GaN in the top contact layer due to the low conductivity of the former layer. Both the (Ga,Mn)N/InGaN diodes and control samples without Mn doping show no or very low (up to 10% at the lowest temperatures) optical (spin) polarization at zero field or 5 T, respectively. The observed polarization is shown to correspond to the intrinsic optical polarization of the InGaN MQW, due to population distribution between spin sublevels at low temperature, as separately studied by resonant optical excitation with a photon energy lower than the bandgap of both the GaN and (Ga,Mn)N. This indicates efficient losses in the studied structures of any spin polarization generated by optical spin orientation or electrical spin injection. The observed vanishing spin injection efficiency of the spin light-emitting diode (LED) is tentatively attributed to spin losses during the energy relaxation process to the ground state of the excitons giving rise to the light emission.     

An increase in the electron mobility in the two-barrier AlGaAs/GaAs/AlGaAs heterostructure as a result of introduction of thin InAs barriers for polar optical phonons into the GaAs quantum well

Confinement and localization of optical phonons in narrow phonon wells with thin phonon barriers decreases the rate of electron-phonon scattering by polar optical phonons by a factor of many times. An increase in mobility and drift velocity of electrons is experimentally observed in strong electric fields upon introduction of thin phonon barriers into the AlGaAs/GaAs/AlGaAs quantum well.     

Carbon and Nickel Oxide/Carbon Composites as Electrodes for Supercapacitors

The carbon and nickel oxide/carbon composite electrodes were prepared by plasma jet and magnetron sputtering techniques.The investigations were performed to evaluate the influence of the Ar/C 2 H 2 ratio on the specific capacitance values of carbon and NiO/carbon electrodes.The obtained electrodes were investigated by scanning electron microscopy,Raman scattering spectroscopy(RS),and X-ray diffraction techniques.The surface of the carbon electrodes became less porous and more homogenous with increasing Ar/C 2 H 2.The RS results indicated that the fraction of the sp 2 carbon sites increased with increasing Ar/C 2 H 2 ratio.The increase of the Ar/C 2 H 2 ratio increased the capacitance values from 0.73 up to 3.6 F/g.Meanwhile,after the deposition of the nickel oxide on the carbon,the capacitance increased ten and more times and varied in the range of 7.6-86.1 F/g.