Laser synthesis of copper oxides 2D structures with high Seebeck coefficient and high thermoelectric figure of merit

Semiconductors are considered promising materials of thermo-converters and thermo-sensors. The photons generated by a KrF laser source (λ = 248 nm, τFWHM ≤ 25 ns) were used for the synthesis of stable crystalline phases of copper oxides 2D single-layered semiconductor structures via the reaction of ablated copper atoms with oxygen molecules by reactive pulsed laser deposition (RPLD). Obtained semiconductor 2D single-layered structures of (23–75) nm thickness were deposited on 293, 600 or 800 K   Si substrates in oxygen atmosphere at 1.0, 3.0 and 5.0 Pa. X-ray diffraction analysis evidenced polycrystalline structures of the deposits reviled of two crystalline semiconductor phases CuO (002) and CuO(111). Semiconductor temperature trend was detected with variable energy band gap (Eg) in the range of (0.10–1.5) eV depending on substrate temperature, oxygen pressure and structure thickness. The optimum conditions were found out when the S coefficient was being homogeneously increased from 2.0 mV/K up to 10.5 mV/K and thermoelectric figure of merit (ZT) from 0.0035 up to 9.0 in the range of (290–340) K. The interpretation of behaviour for these 2D single-layered semiconductor structures of thermoelectric properties was provided. Obtained 2D single-layered structures based on copper oxides with such high S coefficient and high ZT are exceptionally strong candidates for a new effective thermo-sensors and thermo-converters operating at moderate temperature. Moreover, RPLD serves as an up to date method for the synthesis of 2D structures with such superior thermo-sensor and thermo-converter properties. These 2D single-layered structures based on copper oxides are among the most promising candidates based on non-toxic precursors for “green” technology fabrication of efficient thermo-sensors and thermo-converters.