Effective Passivation of Black Silicon Surfaces via Plasma‐Enhanced Chemical Vapor Deposition Grown Conformal Hydrogenated Amorphous Silicon Layer. Issue 1 (24th October 2019)

• Record Type: Journal Article
• Authors: Özkol, Engin; Procel, Paul; Zhao, Yifeng; Mazzarella, Luana; Medlin, Rostislav; Šutta, Pavol; Isabella, Olindo; Zeman, Miro
• Is Part Of: Physica status solidi. Volume 14:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-10-24
• Subjects: black silicon -- conformal growth -- hydrogenated amorphous silicon -- plasma-enhanced chemical vapor deposition -- surface passivation; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201900087
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : 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 Al2 O3 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. Abstract : Herein, a route to effectively passivate black silicon (b‐Si) surfaces by plasma‐enhanced chemical vapor deposition (PECVD)‐grown conformal layers of hydrogenated amorphous silicon (a‐Si:H) is presented. With this approach, the effective minority carrier lifetimes can reach up to 2.3 ms. Conformal growth is shown. Passivated samples exhibit less than 4% reflection from 430 to 1020 nm.