High-haze and wide-spectrum hydrogenated MGZO TCO films on micro-textured glass substrates for thin-film solar cells

• Wet-chemically etched glass substrates with large crater-like feature were obtained.
• Wide-spectrum HMGZO-TCO films on micro-textured glass have been developed.
• The textured glass/HMGZO presented stronger light scattering capability.
• Optical band gap value of HMGZO films was above 3.7 eV.
• Solar cells with textured glass/HMGZO showed higher conversion efficiency.

High-haze and wide-spectrum hydrogenated Mg and Ga co-doped ZnO (HMGZO) transparent conductive oxide films on ‘U-shaped’ micro-textured glass are developed using magnetron sputtering. The wet-chemically etched glass substrates with large crater-like features obtained via a frosting method exhibit strong light-scattering capability in a wide wavelength range (~350–1100 nm). The morphological, structural, optical and electrical properties of HMGZO films on textured and flat glass are investigated in detail. The HMGZO thin films deposited on textured glasses show conformal growth and have a polycrystalline hexagonal wurtzite phase with a c-axis preferred orientation, which is similar to that of films deposited on flat glass. The electrical resistivity of HMGZO films decreases from 9.74×10−4 to 7.67×10−4 Ω cm and the optical band gap Eg is in the range from 3.76 to 3.72 eV as the deposition time is increased from 25 to 40 min. The HMGZO films with textured glass substrate exhibit stronger light-scattering capability compared with films with flat glass substrate. Finally, an a-Si solar cell deposited on textured glass shows a higher conversion efficiency and short-circuit current density than that deposited on flat glass, as a result of effectively improved light scattering. ZnO-TCO films on low-cost chemically etched glass substrates are promising candidates as front electrodes for thin-film solar cells.