Ellipsometry Characterization of Hydrogenated Amorphous Silicon Layers Formed on Textured Crystalline Silicon Substrates

Abstract

Hydrogenated amorphous silicon (a-Si:H) layers formed on textured single crystalline silicon (c-Si) substrates have been characterized by spectroscopic ellipsometry using a tilt angle measurement configuration. The a-Si:H layer thickness determined by this technique (58 AE 2 A) shows excellent agreement with that evaluated from transmission electron microscopy (56 AE 5 A). Although no structural change has been observed between a-Si:H layers deposited on flat and textured substrates, the a-Si:H layer thickness was found to decrease by 30% on the textured substrates. The above results demonstrate that the tilt angle ellipsometry measurement is quite effective in characterizing a-Si:H layers incorporated in textured a-Si:H/c-Si heterojunction solar cells. #

Fast determination of the current loss mechanisms in textured crystalline Si-based solar cells

“…As confirmed previously, [33][34][35][36] thin film structures formed on the {111} facets of c-Si pyramid textures can be modeled using a simple coherent optical model. In fact, when a SiN x or an ITO layer (~70 nm) is deposited on the pyramid-shaped random texture, the surface shows a blue color, which corresponds to the interference color of the thin film structure.…”

“…In addition, when the specular light-reflection component of the textures is measured by spectroscopic ellipsometry (SE) using a tilt-angle optical configuration, a-Si:H/c-Si solar cell structures deduced by SE show excellent agreement with those determined by transmission electron microscopy. 34,35 Figure 3 Quite fortunately, for this calculation, the identical calculation procedure described in the previous section (Sec. III A) can be employed.…”

Simulation and application of external quantum efficiency of solar cells based on spectroscopy

“…(15), corresponding optical loss (gains) could be analyzed in the same way as the case in the flat HIT solar cells. It should also be noted that the top angle of pyramid-shaped texture is confirmed to be 80°[ 42,43] and the calculated refractive index of ITO, p-a-Si:H, i-a-Si:H and c-Si are 1.93, 3.58, 3.65 and 3.54, which results in transmission angles of Air/ITO, ITO/p-a-Si:H and p-a-Si:H/i-a-Si:H, i-a-Si:H/c-Si of 24°, 13°, 13° and 13°, respectively. Consequently, in the calculation process of textured solar cell, a normal incidence of light is assumed because the transmission angles are close to the normal to the {111} texture-facet plane [6] .…”

Characterization of μc-Si:H/a-Si:H tandem solar cell structures by spectroscopic ellipsometry

“…In our SE analysis, the calculation of the () spectra has been performed using which textured c-Si samples are tilted so that the specular light reflection on the texture facets is measured [21][22][23]. For the precise calculation of the light reflection on textured surfaces, on the other hand, other approaches including rigorous coupled-wave analysis (RCWA) could be used [24].…”