The stereometric and fractal concepts are crucial tools to analyse, to verify, to report 3‐D microtexture of thin film surfaces on the nanometre scale and thereby to generate useful topographic characteristics for better understanding and steering them toward further improvements and rational use in modern applications. At first, the present work aimed to prepare hematite α‐Fe2O3 thin films with (0, 2, 4, 6 and 8 wt%) of Cu doping by using the air pneumatic spray method. Subsequently, the obtained pure α‐Fe2O3 and Cu‐doped α‐Fe2O3 thin films were characterised by XRD device, which determines their polycrystalline nature with the rhombohedral hematite structure. Analysis by UV‐VIS absorption showed that the transmittance of the thin films is extinct in the wavelength from approximately 500 to 800 nm, revealing that the films have good optical absorbance in the visible region. The obtained bandgap values varied between 2.23 and 2.21 eV. At second stage, the stereometric and fractal analysis are applied on 3‐D image data of pure α‐ Fe2O3 and Cu‐doped α‐Fe2O3 thin films, which in prior generated using AFM device. Accordingly, the obtained statistical parameters such as surface roughness, density distribution of peaks, depths etc. were used to understand the influence of Cu doping on the 3D microtexture of pure α‐ Fe2O3 and Cu‐doped α‐ Fe2O3 thin film surfaces.

This work reviews the effect of Geometrical, physical and electrical parameters of the polycristalline CIGS thin film used as absorber materials in substrate CuIn 0.7 Ga 0.3 Se 2 (CIGS) solar cells. Two-dimensional device simulator Atlas SILVACO-TCAD was employed to study the performances of ZnO:Al/CdS/CIGS/Metal solar cell structure. The impacts of the grain sizes and the grain boundaries (GBs) in the polycrystalline p-CIGS absorber layer have been investigated. The variation of grain sizes in the CIGS bulk was studied and the corresponding design optimization was provided. The best energy conversion efficiencies have been obtained with large grain sizes higher than 2 μm for 3 μm-CIGS thick. The simulation results predict a strong detrimental effect of GBs recombination, which is enhanced by the presence of small width in the direction that attracts minority carriers. An efficiency of 17.1% (with V oc 0.68 V, J sc 34 mA/cm 2 and FF 0.77) has been achieved with small width at about 3 nm. The presence of the valence-band offset in the absorber layer is benign to solar cell performance by limit the carriers recombination. The valence-band offset is predicted to be 0.4 eV in magnitude and localized to a very thin layer at the grain surface in which the surface reconstruction takes place. All these simulation results give some important indication to lead a higher efficiency of polycrystalline CIGS solar cells for feasible fabrication.

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