We performed interfacial electric and electronic studies of both in-situ and ex-situ atomic-layer deposited (ALD) Al₂O₃ films on InGaAs. Self-aligned inversion-channel metal-oxide-semiconductor field-effect-transistors (MOSFETs) with a 1 μm gate length (L_g) from the in-situ sample have extrinsic drain currents (I_d) of 1.8 mA/μm, transconductances (G_m) of 0.98 mS/μm, and an effective mobility (μ_eff) of 1250 cm²/V s. MOSFETs that employ ex-situ ALD-Al₂O₃ have an I_d of 0.56 mA/μm, G_m of 0.28 mS/μm, and μ_eff of 410 cm²/V s. Synchrotron radiation photoemission reveals no AsO_x residue at the Al₂O₃/InGaAs interface using the in-situ approach, whereas some AsO_x residue is detected using the ex-situ method.

We report on the single crystal growth of the single-layer perovskite cobaltate LaSrCoO₄ that was grown by the optical floating zone method using high oxygen pressures. Phase purity and single crystallinity were confirmed by X-ray diffraction techniques. The pure Co³⁺ oxidation state was confirmed by X-ray absorbtion spectroscopy measurements. A transition to a spin glass state is observed at ∼7 K in magnetic susceptibility and specific heat measurements.

High-resolution synchrotron radiation photoemission was employed to study the effects of atomic-layer-deposited trimethylaluminum (TMA) and water on Ga-rich GaAs(001)-4 × 6 and As-rich GaAs(001)-2 × 4 surfaces. No high charge states were found in either As 3d or Ga 3d core-level spectra before and after the deposition of the precursors. TMA adsorption does not disrupt the GaAs surface structure. For the (4 × 6) surface, the TMA precursor existed in both chemisorbed and physisorbed forms. In the former, TMA has lost a methyl group and is bonded to the As of the As-Ga dimer. Upon water purge, the dimethylaluminum-As group was etched off, allowing the now exposed Ga to bond with oxygen. Water also changed the physisorbed TMA into the As-O-Al(CH3)2 configuration. This configuration was also found in 1 cycle of TMA and water exposure of the (2 × 4) surface, but with a greater strength, accounting for the high interface defect density in the mid-gap region.