Fabrication of Transparent ITO/Ga-Doped ZnO Coating as a Front Panel Electrode toward Efficient Thin Film Solar Cells

Abstract

Bi-layer coatings from sputtered indium tin oxide (ITO) and gallium doped zinc oxide (Ga:ZnO) were investigated for transparency in the visible range of the electromagnetic spectrum, optical rejection ability in the near infrared spectrum and conductivity for the novel quantum dot-based solar cells. The multilayer stack produced at optimal oxygen partial pressure exhibits improved optical properties without worsening the electrical ones, even after additional oxidation during the reactive sputtering of the metal-oxides. With a mean optical transmittance of 91.3% in the visible region, mean optical rejection greater than 65% in the infrared range and resistivity lower than 0.4 × 10−2 Ω.cm, this coating is good candidate for front panel electrode in the CdS/ZnS core-shell quantum dot-based solar cells.

Ga-Doped ZnO Coating—A Suitable Tool for Tuning the Electrode Properties in the Solar Cells with CdS/ZnS Core-Shell Quantum Dots

“…Figure 3 showed comparison between the AFM images and average roughness of GZO single film, ITO/GZO bi-layer system without oxidation and ITO/GZO at additional oxidation of 10% and 20%. Electrical resistance of the bi-layer system ITO/GZO at different total sputtering pressures due to additional target oxidation [31].…”

“…It can be seen that the single layer GZO and ITO/GZO without oxidation exhibited relatively low rejection ability of the IR component-the mean reflectance is 15-20%, which means that the transmission in the VIS and NIR ranges is almost the same (average Figure 5. Optical reflectionin the NIR range of single layer of GZO and bi-layercoatings ITO/GZO without and with additional oxidation during sputtering [31].…”

“…Figure 2. Electrical resistance of the bi-layer system ITO/GZO at different total sputtering pressures due to additional target oxidation[31].…”

“…Figure 4. Optical transmittance in the UV-VIS range of single layer of GZO and bi-layer coatings ITO/GZO without and with additional oxidation during sputtering[31].…”