TY - JOUR A1 - Caban, Piotr A1 - Pietruszka, Rafał A1 - Kaszewski, Jarosław A1 - Ożga, Monika A1 - Witkowski, Bartłomiej S. A1 - Kopalko, Krzysztof A1 - Kuźmiuk, Piotr A1 - Gwóźdź, Katarzyna A1 - Płaczek-Popko, Ewa A1 - Lawniczak-Jablonska, Krystyna A1 - Godlewski, Marek T1 - Impact of GaAs(100) surface preparation on EQE of AZO/Al2O3/p-GaAs photovoltaic structures JF - Beilstein Journal of Nanotechnology PY - 2021/// VL - 12 SP - 578 EP - 592 SN - 2190-4286 DO - 10.3762/bjnano.12.48 PB - Beilstein-Institut JA - Beilstein J. Nanotechnol. UR - https://doi.org/10.3762/bjnano.12.48 KW - atomic layer deposition KW - external quantum efficiency KW - gallium arsenide KW - photovoltaics KW - surface passivation N2 - In order to effectively utilize the photovoltaic properties of gallium arsenide, its surface/interface needs to be properly prepared. In the experiments described here we examined eight different paths of GaAs surface treatment (cleaning, etching, passivation) which resulted in different external quantum efficiency (EQE) values of the tested photovoltaic (PV) cells. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) examinations were conducted to obtain structural details of the devices. X-ray photoelectron spectroscopy (XPS) with depth profiling was used to examine interface structure and changes in the elemental content and chemical bonds. The photoluminescence (PL) properties and bandgap measurements of the deposited layers were also reported. The highest EQE value was obtained for the samples initially etched with a citric acid-based etchant and, in the last preparation step, either passivated with ammonium sulfide aqueous solution or treated with ammonium hydroxide solution with no final passivation. Subsequent I–V measurements, however, confirmed that from these samples, only the sulfur-passivated ones provided the highest current density. The tested devices were fabricated by using the ALD method. ER -