Recent and forthcoming publications in pss

High-temperature thermoelectric properties of Cu2In4Te7

Theerayuth Plirdpring, Ken Kurosaki, Atsuko Kosuga, Manabu Ishimaru, Yuji Ohishi, Hiroaki Muta, and Shinsuke Yamanaka

Power-generation devices have been developed that use thermoelectric (TE) energy to convert waste heat into electrical energy. Their efficiency depends on the TE properties of the materials and the temperature gradient across the devices. Cu2Ga4Te7 has been reported to have a relatively high thermoelectric figure of merit (ZT). However, the TE properties of Cu2In4Te7, which has the same defect zinc-blende structure, have been hardly investigated and are addressed in this Letter. In the Cu2In4Te7 structure, a seventh of the cation sites are structural vacancies. As a result of phonon scattering by structural vacancies, Cu2In4Te7 exhibits low lattice thermal conductivity and thus a relatively high thermoelectric figure of merit.

Phys. Status Solidi RRL (2012) DOI 10.1002/pssr.201206058

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Whispering gallery modes in deformed hexagonal resonators

Marius Grundmann and Christof P. Dietrich

Whispering gallery modes (WGM) are resonances due to total internal reflection (TIR) with a typically large quality factor. Grundmann and Dietrich theoretically analyze WGM in planar hexagonal resonators using ray optics. In a uniform hexagon, the nature of 3-WGM (with three reflections) is discussed in detail, taking into account double-triangular round trips. Three types of deformation are investigated for ZnO microwires. For a dodecagon boundary, WGM with 3, 4, 6, and 12 reflections are analyzed. For non-uniform, elongated hexagons, 6-WGM and 3-WGM are stable. For bent (uniaxially stressed) hexagonal resonators, only the 3-WGM modes were found stable.

WGM have been discovered in St. Paul's cathedral, London, hundred years ago by Lord Rayleigh.

Phys. Status Solidi B (2012) DOI 10.1002/pssb.201100159

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Sharp contrast of the density and size of Ga metal droplets on photolithographically patterned GaAs (100) by droplet epitaxy

M.-Y. Li, J. Lee, Z. Wang, Y. Hirono, J. Wu, S. Song, S.-M. Koo, E.-S. Kim, and G. J. Salamo

Droplet epitaxy is gaining significant research interest for the fabrication of low dimensional semiconductor quantum- and nano-structures by self-assembly. Control of the density and size of metal droplets (MDs) on patterned GaAs (100) surface has become an essential step for further development. Ming-Yu Li et al. present an attempt to demonstrate the sharp contrast of the size and density of Ga MDs on patterned GaAs (100) surface through conventional photolithography. As clearly evidenced by scanning electron and atomic force microscopies, the MD density between etched (patterned) and un-etched (un-patterned) surfaces can be sharply different up to one order of magnitude under identical growth conditions.

Phys. Status Solidi A (2012) DOI 10.1002/pssa.201127692

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