Optoelectrical modeling of solar cells based on c-Si/a-Si:H nanowire arrays: focus on the electrical transport in between the nanowires

Alexandra Levtchenko (1) , Sylvain Le Gall (1) , Raphaël Lachaume (1, 2) , Jérôme Michallon (2, 1, 3) , Stéphane Collin (4, 3) , José Alvarez (1) , Zakaria Djebbour (1) , Jean-Paul Kleider (1)

1 GeePs - Laboratoire Génie électrique et électronique de Paris
2 IPVF - Institut Photovoltaïque d’Ile-de-France (ITE)
3 C2N - Centre de Nanosciences et de Nanotechnologies [Marcoussis]
4 LPN - Laboratoire de photonique et de nanostructures

By coupling optical and electrical modeling, we have investigated the photovoltaic performances of p-i-n radial nanowires array based on crystalline p-type silicon (c-Si) core/hydrogenated amorphous silicon (a-Si:H) shell. By varying either the doping concentration of the c-Si core, or back contact work function we can separate and highlight the contribution to the cell's performance of the nanowires themselves (the radial cell) from the interspace between the nanowires (the planar cell). We show that the build-in potential (Vbi) in the radial and planar cells strongly depends on the doping of c-Si core and the work function of the back contact respectively. Consequently, the solar cell's performance is degraded if either the doping concentration of the c-Si core, or/and the work function of the back contact is too low. By inserting a thin (p) a-Si:H layer between both core/absorber and back contact/absorber, the performance of the solar cell can be improved by partly fixing the Vbi at both interfaces due to strong electrostatic screening effect. Depositing such a buffer layer playing the role of an electrostatic screen for charge carriers is a suggested way of enhancing the performance of solar cells based on radial p-i-n or n-i-p nanowire array.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Micro et nanotechnologies/Microélectronique; Energie électrique

Alexandra Levtchenko, Sylvain Le Gall, Raphaël Lachaume, Jérôme Michallon, Stéphane Collin, et al.. Optoelectrical modeling of solar cells based on c-Si/a-Si:H nanowire arrays: focus on the electrical transport in between the nanowires. Nanotechnology, 2018, nanotechnology, 29 (25), pp.255401. ⟨10.1088/1361-6528/aab7e8⟩. ⟨hal-01738024⟩