ZnO Films with Very High Haze Value for Use as Front Transparent Conductive Oxide Films in Thin-Film Silicon Solar Cells

Abstract

We successfully increased the haze value of zinc oxide (ZnO) films fabricated using metal–organic chemical vapor deposition (MOCVD) by conducting glass-substrate etching before film deposition. It was found that with increasing the glass treatment time, the surface morphology of ZnO films changed from conventional pyramid-like single texture to greater cauliflower-like multi texture. Further, the rms roughness and the haze value of the films increased remarkably. Using ZnO films with a high haze value as front transparent conductive oxide (TCO) films in hydrogenated microcrystalline silicon (µc-Si:H) solar cells, we improved the quantum efficiency of these cells particularly in the long-wavelength region.

Nanoimprint Lithography for High-Efficiency Thin-Film Silicon Solar Cells

“…[13][14][15] Light scattering at nanotextured interfaces provides a powerful and proven alternative to improve the optical performance of thinfilm silicon devices. [16][17][18][19][20][21][22][23][24][25][26][27] However, despite intensive experimental and theoretical efforts, neither the ideal interface morphology nor the ideal scattering characteristics have been identified to date. From an experimental point of view, one desires a method that allows one to evaluate and compare the light-trapping capabilities of specifically designed photonic nanostructures directly in the device.…”

Modulated surface textures for enhanced light trapping in thin-film silicon solar cells

“…To meet this demand, TCO substrates with different surface textures have recently been developed and tested in solar cells, such as optimized wet-etched 4 or surface plasma-treated 5 zinc-oxide, double-textured tin-oxide, 6 and a combination of etched glass with zinc-oxide. 7 Even though the potential of using of high performance TCOs has been already investigated, 8 a physical explanation of why these textures result in high scattering properties is still missing.In this paper we introduce and analyze a more general concept of surface textures for enhanced scattering in a broad wavelength range, namely a modulated surface texture. We demonstrate that the enhanced scattering is achieved by superposition of different scattering mechanisms caused by the different geometrical features integrated in a modulated surface texture.…”

“…To meet this demand, TCO substrates with different surface textures have recently been developed and tested in solar cells, such as optimized wet-etched 4 or surface plasma-treated 5 zinc-oxide, double-textured tin-oxide, 6 and a combination of etched glass with zinc-oxide. 7 Even though the potential of using of high performance TCOs has been already investigated, 8 a physical explanation of why these textures result in high scattering properties is still missing.…”

Structural and Optical Properties of Smooth Surface TCO Thin Films Deposited on Different-Sized Staked Nanoparticle Layers for Window Electrode of Thin Film Si Solar Cells

“…13) To maximize incident light absorption within the Si thin films, a sufficiently thick Si layer is required. However, poor carrier diffusion properties of Si thin films prohibit the use of thick Si layers for thin film solar cells.…”