• Procel, Paul
• Zhao, Yifeng
• Mazzarella, Luana
• Isabella, Olindo
• Özkol, Engin
• Medlin, Rostislav
• Šutta, Pavol
• Zeman, Miro

Abstract

<p>Solar cells based on black silicon (b-Si) are proven to be promising in photovoltaics (PVs) by exceeding 22% efficiency. To reach high efficiencies with b-Si surfaces, the most crucial step is the effective surface passivation. Up to now, the highest effective minority carrier lifetimes are achieved with atomic layer-deposited Al₂O₃ or thermal SiO₂. Plasma-enhanced chemical vapor deposition (PECVD)-grown hydrogenated amorphous silicon (a-Si:H) passivation of b-Si is seldom reported due to conformality problems. In this current study, b-Si surfaces superposed on standard pyramidal textures, also known as modulated surface textures (MSTs), are successfully passivated by PECVD-grown conformal layers of a-Si:H. It is shown that under proper plasma-processing conditions, the effective minority carrier lifetimes of samples endowed with front MST and rear standard pyramidal textures can reach up to 2.3 ms. A route to the conformal growth is described and developed by transmission electron microscopic (TEM) images. Passivated MST samples exhibit less than 4% reflection in a wide spectral range from 430 to 1020 nm.</p>

Topics

• impedance spectroscopy
• surface
• amorphous
• laser emission spectroscopy
• mass spectrometry
• transmission electron microscopy
• texture
• Silicon
• chemical vapor deposition