Electronic transport properties of BixTey-infiltrated synthetic opals

We have demonstrated that crystalline Bi_xTe_y can be grown directly inside the 100-200 nm diameter pores of a synthetic opal host using a metal-organic chemical vapor deposition (MOCVD). A series of Bi_xTe_y-infiltrated opal samples have been characterized by X-ray powder diffraction, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDXS). Thermoelectric power values in the infiltrated opal samples ranged from -70 μV/K to +200 μV/K at room temperature T=300 K for the Bi- and the Te-rich Bi₂Te₃ compositions, respectively. The n-type (Bi-rich) samples were found to exhibit metallic electrical resistivity R (dR/dT>0) from 10 to 300 K, while the p-type (Te-rich) samples demonstrated negative dR/dT