C.H. Sun

High-temperature solar cell for concentrated solar-power hybrid systems

A high-temperature solar cell is proposed that harvests solar energy at elevated temperatures. Carrier separation is achieved by selective contacts that preferentially extract electrons or holes. The theoretical conversion efficiency of the proposed device is 38.6% at 600 K and an incident solar radiation concentration of 1000. The waste heat of this cell could be used by a secondary thermal converter boosting the total efficiency of the hybrid system above 55%.

Packing-dependent pore structures in single-walled carbon nanotube arrays

Based on a self-similar array model of single-walled carbon nanotubes (SWNTs), the pore structure of SWNT bundles is analyzed and compared with that obtained from the conventional triangular model and adsorption experimental results. In addition to the well known cylindrical endo-cavities and interstitial pores, two types of newly defined pores with diameters of 2-10 and 8-100 nm are proposed, inter-bundle pores and inter-array pores. In particular, the relationship between the packing configuration of SWNTs and their pore structures is systematically investigated. (c) 2005 American Institute of Physics.

Electronic transitions and hybrid resonance in InAsSb films by reflectance spectra

Electronic properties of InAs1−xSbx films with x up to 0.09 have been investigated by reflectance spectra in 1.5–5 eV energy range at room temperature. The real and imaginary parts of the dielectric function were derived by Kramers–Kronig analysis on the reflectance spectra, which show satisfactory agreement with the spectroscopic ellipsometry data. The E1′ and E1′+Δ1′ peaks are attributed to electronic interband transitions at the E1 and E1+Δ1 critical points, respectively. The prominent E2′ peaks, which exhibit high reflectivity and large blueshift, are found to be contributed by hybrid resonance due to the cooperative behavior of both E2-state electrons and plasmons.