Laser synthesis of 2D structures for photo-thermo sensors with high sensitivity

Abstract

Semiconductors are considered as promising materials for the fabrication of photo-thermo sensors with high sensitivity. Therefore, here we propose to synthesize of amorphous 2D single-layered structures with high thermo-photosensitivity by using photons generated by a KrF* laser radiation (λ = 248 nm, τFWHM ≤ 25 ns) in the reaction of copper (Cu) atoms with methane (CH4) molecules by reactive pulsed laser deposition (RPLD) process. Optimum conditions were found out to synthesize of these structures with the thickness of (56–160) nm. X-ray diffraction analysis evidenced either amorphous or polycrystalline structures on the deposits. Element analysis was carried out by energy-dispersive X-ray spectroscopy (EDXS). The semiconductor temperature trend was detected with the variable energy band gap (Eg) in the range of (0.17–1.0) eV depending on substrate temperature, CH4 pressure and structures’ thickness. The highest photosensitivity of these structures was high as 640 V/W at white light power density ~ 6 × 10–3 W/cm2 and the highest thermo-sensitivity (Seebeck coefficient) was high as 10.5 mV/K. An interpretation is provided for thermo-photosensitivity behaviour. The amorphous 2D single-layered structures were synthesized by laser radiation for the first time with such superior thermo-photo properties. Therefore, such structures are exceptional candidates for a new generation of effective thermo-photo sensors operating at moderate temperatures.