用于光伏应用的Cu(In1-xGax)Se2薄膜的温度依赖性生长与表征

Thin films of Cu(In 1-x Ga x )Se 2 (CIGS) were synthesized by thermal annealing of a Cu/In/Ga/Se stack deposited using the multisource sequentially evaporation layer deposition technique. The precursor layers were deposited under a vacuum of ~ 1 × 10 –4 Pa using thermal evaporation. The as-deposited stack was annealed at temperatures ranging from 473 K to 623 K, with a 50 K interval, in a vacuum of 10 –1 Pa. The nanostructured crystallites of the grown layers were analyzed using X-ray diffraction method. Mixed phases of CuSe, CIGS, and Se were observed at temperatures of 473 K and 523 K, while single-phase CIGS thin films were formed at 573 K and 623 K. The CIGS thin films crystallize in a tetragonal crystal system, with unit cell parameters of a = b = 5.758(7) Å, c = 11.645(3) Å, and a unit cell volume of 386 Å 3 . The average crystallite size (D) ranges from 16 to 28 nm. The bandgap (E g ) of the CIGS films varies between 1.10 eV and 1.53 eV, while the absorption coefficient spans from 2 × 10 4 cm −1 to 6 × 10 4 cm −1 in the entire annealing temperature (T A ) range. The single-phase CIGS thin films exhibited a resistivity (ρ) of 2.37 Ω-cm, a mobility (μ) of 4.53 cm 2 /V-s, and a carrier concentration (N A ) of 4.86 × 10 14 cm −3 at 573 K, indicating their suitability for use as the absorber layer in solar cell structures.