The Application Of Condensed Matter Spectroscopy In Silicon Solar Cells

Generating electricity by solar cells becomes one of the significant ways to solve the shortage of energy and environment pollution. Currently, more than 80% solar cells are made from crystalline silicon, so it is very important to develop high efficiency and low cost silicon solar cells. An effective procedure is to deposit hydrogenated amorphous silicon nitride (a-SiN_x:H) anti-reflection coatings (ARCs) on silicon solar cells. And as an important experimental method, condensed matter spectroscopy is widely applied to inspect the properties of silicon substrates and ARCs of silicon solar cells.Based on the density of occupied states and carrier-phonon interaction of Urabch tail theory, we improve the absorption coefficient model and analyze the band tail characteristics of crystalline silicon substrates using the transmission spectra. We correlate the relationship between the band tail parameters and trap concentration. As a-SiN_x:H thin films are generally deposited on crystalline silicon substrates, their optical constants (refractive index, absorption/extinction coefficient, optical band gap, and Urbach tail) usually cannot be retrieved only by experimental measurements, but have to resort to other analytical methods. Here, we adopt a reflection equation which takes into account the extinction coefficient of the substrate for an air/film/substrate/air configuration. By comparing the physical natures of the Adachi, Forouhi-Bloomer, and Tauc-Lorentz models, we propose a Tauc- Lorentz-Urbach (TLU) model with inclusion the Urbach tail. As a result, the...