The effects of growth conditions on the size and density of self-assembled InAlAs/AlGaAs quantum dots (QDs) grown on GaAs by molecular beam epitaxy (MBE) were studied, with an emphasis on their use for single QD spectroscopy. The effects of substrate temperature and growth rate on the density and size were found to be quite similar to those of InAs QDs on GaAs.The effect of coverage, however, was different. Although the density was relatively high as compared to that of InAs QDs, it was reduced to 1 × 10 10 cm -2 under an optimized condition. This density is compatible with single QD spectroscopy with the help of a certain nanofabrication technique for areal restriction.

We report low-resistive Au ohmic contact for a molecular beam epitaxy grown nitrogen doped p-type ZnTe (p-ZnTe:N) layer with high thermal stability, where the p-ZnTe surface is treated by oxygen plasma and HCl solution prior to Au film deposition. C contamination and native oxide layers of ZnTe are removed by oxygen plasma and HCl treatment, respectively, from the surface. As a result, a Te-rich layer is formed on the surface. The annealing temperature dependence of specific contact resistance is investigated. The specific contact resistance of Au ohmic contact for p-ZnTe:N with carrier concentration of 2×1018 cm−3 treated by oxygen plasma and HCl solution reaches as low as 5.8×10−6 Ω cm2 at an annealing temperature of 350 °C. This specific contact resistance value is the same as that of the reported Pd/(Pt)/Au contact for p-ZnTe:N with carrier concentration of 3×1019 cm−3, and clearly shows higher thermal stability.

We studied the size distribution and its scaling behavior of self-assembled InAlAs/AlGaAs quantum dots (QDs) grown on GaAs with the Stranski-Krastanov (SK) mode by molecular beam epitaxy (MBE), at both 480°C and 510°C, as a function of InAlAs coverage. A scaling function of the volume was found for the first time in ternary alloy QDs. The function was similar to that of InAs/GaAs QDs, which agreed with the scaling function for the two-dimensional submonolayer homoepitaxy simulation with a critical island size of i = 1. However, a character of i = 0 was also found as a tail in the large volume.

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The stress corrosion cracking (SCC) of pure copper poly-and single crystals in NaNO2 solutions was investigated potentiostatically by the slow strain rate technique. The susceptibility to SCC has a maximum in 1kmol・m-3 NaNO2 solution of 7.3-7.5 pH, at the strain rate below 1.67×10-5s-1. In this solution, a close correlation was found between the SCC and anodic polarization behavior of pure copper: The potential range for SCC occurrence was 0-100mV (SCE), nearly corresponding to that of passivity/transpassivity transition where the formation or rupture of black tarnish film (Cu2O) occurred. The fractographic results showed that many cracks nucleated from the specimen surfaces with frequent slip-steps, producing the tarnish film. The crack propagation was predominantly transgranular, along <110> direction on {110} plane. The evidence introduced here supports an anodic dissolution mechanism for the transgranular SCC of pure copper in NaNO2 solutions, including a tarnish rupture mechanism.