Pierre Carrier

Band structure and fundamental optical transitions in wurtzite AlN

With a recently developed unique deep ultraviolet picoseconds time-resolved photoluminescence (PL) spectroscopy system and improved growth technique, we are able to determine the detailed band structure near the Γ point of wurtzite (WZ) AlN with a direct band gap of 6.12 eV. Combined with first-principles band structure calculations we show that the fundamental optical properties of AlN differ drastically from that of GaN and other WZ semiconductors. The discrepancy in energy band gap values of AlN obtained previously by different methods is explained in terms of the optical selection rules in AlN and is confirmed by measurement of the polarization dependence of the excitonic PL spectra.

Challenges in Representation Learning: A Report on Three Machine Learning Contests

The ICML 2013 Workshop on Challenges in Representation Learning focused on three challenges: the black box learning challenge, the facial expression recognition challenge, and the multimodal learning challenge. We describe the datasets created for these challenges and summarize the results of the competitions. We provide suggestions for organizers of future challenges and some comments on what kind of knowledge can be gained from machine learning competitions.

Theoretical study of the band-gap anomaly of InN

Using a band-structure method that includes the correction to the band-gap error in the local-density approximation (LDA), we find that the band gap for InN is 0.8±0.1eV, in good agreement with recent experimental data, but is much smaller than previous experimental value of ∼1.9eV. The unusually small band gap for InN is explained in terms of the high electronegativity of nitrogen and, consequently, the small band-gap deformation potential of InN. The possible origin of the measured large band gaps is discussed in terms of the nonparabolicity of the bands, the Moss–Burstein shift, and the effect of oxygen. Based on the error analysis of our LDA-corrected calculations we have compiled the band-structure parameters for wurtzite AlN, GaN, and InN.

Calculated spin-orbit splitting of all diamondlike and zinc-blende semiconductors: Effects ofp1∕2local orbitals and chemical trends

We have calculated the spin-orbit

Optical properties of structurally relaxed Si / SiO 2 superlattices: The role of bonding at interfaces

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Challenges in representation learning

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Electron confinement and optical enhancement in S i / S i O 2 superlattices

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Photoluminescence within Crystalline-Si/SiO 2 Single Quantum Wells.

for all diamondlike group IV and zinc-blende group III-V, II-VI, and I-VII semiconductors using the full potential linearized augmented plane wave method within the local density approximation. The

Electronic and Optical Properties of Si/SiO2 Superlattices from First Principles: Role of Interfaces.

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Role of interface suboxide Si atoms on the electronic properties of Si/SiO2 superlattices

coupling is included using the second-variation procedure, including the