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We have systematically investigated the thermoelectric properties of misfit-layered chalcogenide (SnS)1.2(TiS2)2. Surprisingly, an unexpected Cu and Co substitution in the conducting TiS2 layer, acceptor dopant, can induce an exotic enhancement of thermoelectric performance. In particular, the value of dimensionless figure of merit ZT has increased by 33.3% and up to 0.42 at 720K for Cu-substituted (SnS)1.2(Cu0.02Ti0.98S2)2. The present findings demonstrate that large effective mass and low carrier concentration are responsible for the emergence of large Seebeck coefficient and high power factor. Furthermore, the enhanced disorder effect due to the substitution accounts for the decrease of electronic thermal conductivity, while the increased phonon scattering of interlayer between SnS and TiS2 layers leads to the reduction of phononic thermal conductivity. Consequently, the Cu- and Co-substituted (SnS)1.2(TiS2)2 could be considered as a promising candidate of thermoelectric materials. [ABSTRACT FROM AUTHOR]

Al2O2/GeOx/Ge gate stack fabricated by an in situ cycling ozone oxidation (COO) method in the atomic layer deposition (ALD) system at low temperature is systematically investigated. Excellent electrical characteristics such as minimum interface trap density as low as 1.9x1011 cm-2 eV-1 have been obtained by COO treatment. The impact of COO treatment against the band alignment of Al2O3 with respect to Ge is studied by x-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE). Based on both XPS and SE studies, the origin of gate leakage in the ALD-Al2O3 is attributed to the sub-gap states, which may be correlated to the OH-related groups in Al2O3 network. It is demonstrated that the COO method is effective in repairing the OH-related defects in high-k dielectrics as well as forming superior high-k/Ge interface for high performance Ge MOS devices. [ABSTRACT FROM AUTHOR]

Describes the growth of gallium nitride (GaN) on a silicon-(001) substrate with specially designed composite intermediate layers. Metal-organic chemical vapor deposition; Ultrathin amorphous silicon layer; GaN/Al[sub x]Ga[sub 1-x]N (x = 0.20); Photoluminescence and x-ray diffraction spectroscopy.

Proposes a hetero tensile-unstrained-tensile-unstrained-tensile quantum structure. Composition of the quantum structure; Deduction of the energy band configuration; Dependence of the nonlinear optical properties on the distribution of the strain-induced built-in electric field within the quantum structure; Agreement between the calculation and measurement results.

Examines the growth of gallium arsenic phosphide/aluminum gallium arsenide strained-layer quantum wells by low-pressure metalorganic vapor phase epitaxy. Characterization of the wells by photoluminescence (PL) spectroscopy; Result of increasing the excitation power during the PL measurement; Applicability of the quantum well in making optoelectric devices.

Examines the growth of gallium arsenide/GaAs[sub1-x]P[sub x](x=0.13) strained-layer quantum well structure. Exhibition of an ambiguous blue shift of the excitonic transition energy; Observation of distinctive narrowing of photoluminescence line width; Responsibility of internal piezoelectric field to the anomalous phenomena.

We have systematically investigated the thermoelectric properties of misfit-layered chalcogenide (SnS)1.2(TiS2)2. Surprisingly, an unexpected Cu and Co substitution in the conducting TiS2 layer, acceptor dopant, can induce an exotic enhancement of thermoelectric performance. In particular, the value of dimensionless figure of merit ZT has increased by 33.3% and up to 0.42 at 720K for Cu-substituted (SnS)1.2(Cu0.02Ti0.98S2)2. The present findings demonstrate that large effective mass and low carrier concentration are responsible for the emergence of large Seebeck coefficient and high power factor. Furthermore, the enhanced disorder effect due to the substitution accounts for the decrease of electronic thermal conductivity, while the increased phonon scattering of interlayer between SnS and TiS2 layers leads to the reduction of phononic thermal conductivity. Consequently, the Cu- and Co-substituted (SnS)1.2(TiS2)2 could be considered as a promising candidate of thermoelectric materials. [ABSTRACT FROM AUTHOR]