Surface etching effects of amorphous C:H and CNx:H films formed by supermagnetron plasma for field emission use

Supermagnetron plasma was used to deposit amorphous hydrogenated carbon (a-C:H) and hydrogenated carbon nitride (a-CN_x:H) films for field-emission devices using i-C₄H₁₀/(H₂ or N₂). It was also used to improve the field-emission characteristics by surface etching using N₂/H₂ plasma. The best emission threshold electric field (E_TH) was 13 and 12 V/μm for devices using as-deposited a-C:H and as-deposited a-CN_x:H films, respectively, while they were remarkably improved to 11 and 8 V/μm by surface etching using N₂/H₂ (120/40 sccm) gas, though surface roughness was slightly increased by the surface etching. The hardness of as-deposited films was higher than 22 GPa.     

Magnetic sensor with prism coupler

The physical principle of proposed sensor is based on the combination of two effects: the modulation of permittivity tensor elements in materials with induced anisotropy by external magnetic field and the creation of sharp minima in reflectance on prism base at guided mode resonance. As result we can observe pointed up the polarization states of reflected light beam influenced by external magnetic field.

Procedures based on the Yeh’s 4×4 matrix formalism are described for the treatment of the electromagnetic interactions in prism-layered or -bulk structure with magnetic ordering. The tunneling phenomenon between coupling prism and inspected object is analyzed for ultrathin approximation and for the case of a gap spacing wide enough so that the prism could be considered as weak perturbation to the modes of the free structure. The value of Kerr rotation at resonant states achieves to one radian. Its dependence on in-plane modulation of magnetization direction offers the possibility to realize the magnetic vector sensor with angle distinguishing better than one degree.     

熔体外延法生长截止波长8～12μm InAs1-xSbx单晶的透射光谱

用熔体外延法在InAs衬底上成功地生长了截止波长为8～12mm的InAs1-xSbx单晶.用红外光谱仪测量了样品的透射光谱.提出了组分微观分布函数的概念,并计算了InSb单晶和3种不同组分InAs1-xSbx样品的透射光谱.结果表明,实验测得的样品截止波长与计算得到的数据基本一致,从而证实了熔体外延法生长的InAs1-xSbx单晶的禁带宽度变窄现象,并认为组分微观分布的不均匀性可能影响Ⅲ-Ⅴ族混晶的能带结构.     

Magneto-optic ellipsometry in exchange-coupled films

Analytical representations of Jones matrices for the magneto-optic (MO) reflection in (a) a magnetic film on a magnetic substrate separated by a nonmagnetic spacer and (b) two ultrathin magnetic films separated by a nonmagnetic spacer, sandwiched between a nonmagnetic cover and a nonmagnetic substrate with arbitrary and independent orientations of magnetization, are provided. Originally isotropic media subjected to a uniform magnetization are considered. The discussion of MO response is restricted to the terms linear in the off-diagonal permittivity tensor elements, and typical situationsare illustrated numerically. The results are useful for the analysis of the experiments in MO ellipsometry and MO magnetometry of exchange-coupled magnetic ultrathin-film structures.     

High purity InxGa1−xSb single crystals with cutoff wavelength of 7–8 µm grown by melt epitaxy

For the first time, InGaSb single crystals with a cutoff wavelength of 7–8 μm were successfully grown on GaAs substrates by a new growth technique named melt epitaxy. The band gap of InGaSb layers obviously narrowed compared with those with the same compositions grown by ordinary methods and the longest cutoff wavelength reached 8.3 μm. High electron mobility of 8.05×10⁴ cm²/Vs and low carrier density of 1×10¹⁵ cm⁻³ at 77 K were obtained indicating high purity of InGaSb epilayers.