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P-type transparent conductive materials (TCMs) are urgently needed in the development of photoelectric devices. In particular, the P-type TCMs that can be applied in the mid-infrared range are even rarer due to the conflict between the transparent range and the conductivity of materials. In this work, a P-type mid-infrared transparent conductive LaSe2 film is obtained by a two-step method combining the RF sputtering and a selenized annealing process. The crystal structure of the film has been confirmed by x-ray diffraction and Raman spectrum analysis. According to the Hall effect measurement results, the LaSe2 film has a higher conductivity (about 3.6 S/cm) than that of traditional P-type mid-infrared TCMs, which is attributed to its ten times higher carrier concentration (about 1019 cm−3) and a much smaller hole effective mass (about 0.34 me) compared to the conventional P-type mid-infrared TCMs. The transmittance (about 75%) is at the same level as that of the traditional P-type mid-infrared TCMs. In a sense, the LaSe2 is a promising candidate material for the development of mid-infrared photoelectric devices.

Complete sets of elastic, piezoelectric, and dielectric constants of 0.72Pb(Mg(1∕3)Nb(2∕3))O(3)-0.28PbTiO(3) single crystal poled along [111](c) (single domain) as well as non-polar axes [001](c) and [011](c) (multidomain) have been measured under natural conditions. These data allowed us to evaluate accurately the extrinsic contributions to the superior piezoelectric properties. Very large extrinsic contributions to the unusual anisotropies in multidomain crystals are confirmed. We found that the instability of domain structures is the origin of the low mechanical quality factor Q for the multidomain relaxor-based ferroelectric single crystals. Our results can provide useful guidance in future design of domain engineered materials.