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Using the high-brilliant synchrotron radiation at SPring-8 we have studied the SiO2/Si interface structures, the interface state densities, and the uniformities of ∼1-nm-thick oxide films formed by three kinds of atomic oxygen at 300 °C by measuring Si 2p photoelectron spectra at the photon energy of 1050 eV and the energy loss spectra of O 1s photoelectrons at the photon energy of 714 eV. Among silicon oxide films studied here the abrupt compositional transition at SiO2/Si interface, the smallest deviation in interface state density, the interface state density comparable to that for thermal oxide formed in dry oxygen at 950 °C, and the highest uniformity was obtained with oxide film formed in krypton-mixed oxygen (Kr:O2=97:3) plasma.

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ZnTe and ZnSeTe p‐contact layers were investigated for use in BeZnSeTe/MgZnCdSe optical devices on InP sub‐strates. The contact resistances (Rc) of Au electrodes to N‐doped p‐ZnTe and p‐ZnSeTe contact lay‐ers were evaluated using the circular transmission line model (c‐TLM) method. A lower Rc (3.1×10‐3 Ωcm2) was obtained for the ZnSeTe p‐contact sample than for the ZnTe sample (6.3×10‐3 Ωcm2). BeZnSeTe/MgZnCdSe yellow‐light‐emitting devices with a ZnTe or ZnSeTe p‐contact layer grown on InP substrates were characterized. A comparison of the current‐voltage (I‐V) characteristics of these devices showed that the turn‐on voltage of the ZnSeTe contact device was about 4 V lower than that of the ZnTe device. From the aging characteristics of these devices under direct‐current injection at room temperature, it was shown that the lifetime of the ZnSeTe contact device was 30 times longer than that of the ZnTe contact device. These results show that a ZnSeTe contact layer is more suitable for BeZnSeTe/MgZnCdSe optical devices on InP substrates than a ZnTe contact layer. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The origin of the formation of a highly resistive layer around a growth-interrupted interface in GaAs has been studied by capacitance-voltage carrier profiling and deep-level transient spectroscopy. It is concluded that the origin of the highly resistive layer is attributable to the formation of interface states created by exposure of the GaAs surface to air. The Fermi level at the interface is pinned in n-type GaAs, but is not in p-type GaAs.

Indium tin oxide (ITO) transparent electrodes formed on II‐VI compound semiconductor optical devices on InP substrates were characterized. Two kinds of ZnCdSe/BeZnTe p‐n diode devices with a different p‐contact layer (i.e., p‐ZnTe and p‐ZnSeTe layers) were prepared to investigate more suitable p‐contact material for ITO electrodes on the II‐VI devices. Thin ITO layers were deposited on the devices by magnetron sputtering. From injection current density versus applied voltage (J‐V) characteristics, the turn‐on voltage of the ZnTe contact device was found to be lower than that of the ZnSeTe contact device by about 2 V. The J‐V characteristic of the ZnTe device was comparable to that of the device with Au electrodes on the p‐contact instead of ITO. Using ITO electrodes, ZnCdSe/BeZnTe erlattice photovoltaic devices with ZnTe and ZnSeTe p‐contact layers were fabricated. The devices were characterized under 1.5 AM illumination at room temperature. The J‐V characteristics showed that the device performances of the ZnTe contact device were almost erior to those of the ZnSeTe device. Open‐circuit voltage, short‐circuit current density, fill factor, and maximum conversion efficiency of the ZnTe device were 0.90 V, 4.7 A/cm2, 0.35, and 1.5%, respectively. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)