Thermoelectric properties, x-ray photoelectron spectroscopy, Raman spectroscopy, and electronic structures have been studied for Mn-substituted CuInSe2 chalcopyrites. Raman spectroscopy verifies the lattice disorder due to the introduction of Mn into the CuInSe2 matrix, leading to a slight suppression of thermal conductivity. On the other hand, the Mn substitution significantly increases the electrical conductivity and Seebeck coefficient. Therefore the thermoelectric figure of merit ZT has been enhanced by over two orders of magnitude by the introduction of Mn into CuInSe 2. These materials are p-type degenerate semiconductors, containing divalent Mn species as confirmed by x-ray photoelectron spectroscopy. The crystal structure of Mn-substituted CuInSe2, as well as related ternary and quaternary diamond-like semiconductors, can be viewed as a combination of an electrically conducting unit, the Cu-Se and Mn-Se networks, and an electrically insulating unit, the In-Se network. Therefore, diamond-like semiconductors can serve as a potential class of thermoelectric materials with relatively wide band gaps upon substitution with Mn or other transition metals.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Aug 8 2011|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics