c-Si/a-Si:H/indium tin oxide (ITO) heterojunctions have been prepared by electron-beam deposition of an (ITO) thin film on a plasma enhanced chemical vapor deposition grown c-Si/a-Si:H heterojunction. These heterostructures, which are the basis of solar cells, have been annealed in N2atmosphere at temperatures in the range 250-650 °C. Thermal annealing effects on structural and optical properties of the ITO, the a-Si:H layer, and of the c-Si/a-Si interface have been detected by spectroscopic ellipsometry. The optical response of ITO is described in the energy range 1.5-5.0 eV, where a high transparency is required for ITO, by analyzing ellipsometric spectra in terms of a model which combines the Drude model and a double Lorentzian oscillator. Spectroscopic ellipsometry has shown that annealing at T>450 °C causes hydrogen out-diffusion from the a-Si:H layer into the ITO layer whose optical and electrical properties are modified. Additionally, damage of the c-Si/a-Si interface and of the ITO layer by hydrogen diffusion is detected and seen as a factor affecting performance of c-Si/a-Si/ITO stacked structure based solar cells. X-ray photoelectron spectroscopy and atomic force microscopy measurements have corroborated ellipsometric analysis. © 2001 American Institute of Physics.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
Losurdo, M., Giangregorio, M., Capezzuto, P., Bruno, G., Varsano, F., Tucci, M., & Roca, F. (2001). Modifications of c-Si/a-Si:H/indium tin oxide heterostructures upon thermal annealing. Journal of Applied Physics, 90(12), 6505 - 6512. https://doi.org/10.1063/1.1413487