Synthesis and characterization of preferential indium surface deposited CIGSe absorber using a modified three-stage deposition technique

The performance of copper-indium-gallium-selenium (CIGSe) absorber nanomaterials significantly depends on the synthesized layer's synthesis, composition, and properties, including doping with other materials. Understanding the composition and possible preferential deposition of the precursor materials is vital to the absorption properties of the layer. This study examines the structural, morphological, topographical, optical, electrical, and depth profile properties of the selectively deposited absorber layer of the indium top layer. The structural studies confirmed the consistent retention of the preferred chalcopyrite orientation with crystallite sizes up to 44 nm, even with the preferential indium-dominant deposition, confirmed by the observed elemental distribution from the SIMS and EDX results. The morphological studies showed the presence of smaller grain structures with at@16 % gallium concentration inclusion, which could account for the increase in mobility recorded with CIGSe. Raman studies confirmed highly crystalline chalcopyrite structures deposition with A1 characteristic vibration modes, while the AFM characterizations revealed increased grain parameters up to 2.6 μm. Optical characterizations using UV–Vis studies were used to characterize the bandgap (∼1.12 eV for CIGSe) and dielectric properties, which could affect the electrical properties of the layer. The Hall characterizations gave a resistivity of 8.3 × 10⁻² Ω cm for the CISe sample, which increased in the CIGSe sample (10.52 × 10⁻² Ω cm) due to gallium inclusion. However, the carrier mobility conversely improved slightly, from 0.61 to 1.18 cm²/V s.