Emitter controlled SiNx-free crystalline Si solar cells with a transparent conducting oxide film

A transparent conducting oxide (TCO) layer was applied in crystalline Si (c-Si) solar cells without use of the conventional SiNx-coating. A high quality indium-tin-oxide (ITO) layer was directly deposited on an emitter layer of a Si wafer. Three different types of emitters were formed by controlling the phosphorous diffusion conditions. A light-doped emitter forming a thinner emitter junction showed an improved photoconversion efficiency of 14.1% compared to the value of 13.2% for a heavy-doped emitter. This was induced by lower recombination within the narrower depletion region of the light-doped emitter.As for the electrical aspect, the ITO layer serves as an efficient electrical conductor and thus relieves the burden of high contact resistance of the light-doped emitter. From the aspect of light management, the intermediate refractive index of ITO is effective at reducing the light reflection, leading to an enhanced carrier generation in Si absorbers.

Figure optionsDownload as PowerPoint slideHighlights
► Transparent conducting oxide (TCO)-embedded emitters for Si solar cells.
► Indium-tin-oxide (ITO) layer is an efficient electrical conductor and a buffer.