Effects of rapid thermal annealing as back contacts activation treatment on CdS/CdTe multi-contacted solar cells

• Published in: Superlattices and microstructures Vol. 151; p. 106832
• Main Authors: Fernández-Domínguez, E., Torres-Delgado, G., Castanedo-Pérez, R., Márquez-Marín, J., Zelaya-Ángel, O.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2021
• Subjects: Back-contact activation; CdS/CdTe solar Cells; CuxTe; Multiple back-contacts; RTA; CuxTe; CdS/CdTe solar Cells; RTA; Multiple back-contacts; Back-contact activation
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2021.106832

Cd2SnO4/CdS/CdTe/CuxTe/Au structure solar cells were made in samples of 20 × 20 mm2. Multiple metallic back-contacts were deposited on each sample by thermal evaporation. A series of rapid thermal annealing treatments (RTA) were performed on the cells, controlling work pressure (Pw) and temperature (Ta), to activate the interface of CdTe-back contact. Several combinations of pressure (746 mbar ≤ Pw ≤ 1112 mbar) and temperature (180 °C ≤ Ta ≤ 260 °C) were studied. The best results were obtained for the lowest Pw, increasing the average efficiency from 6.9% to 9.8% as Ta increased. All photovoltaic parameters (VOC, JSC, FF, RS, and RSh) were enhanced with the RTA treatments along with the dispersion values. Once the thermal activation's optimal conditions were determined, the highest efficiency was 11.3% with an RTA single treatment. The improvement is attributed to the formation of Cu1·85Te phase. It is shown that this kind of thermal treatment on CuxTe/Au back-contact of the cells can be employed to obtain higher area solar cells. •CuTe/Au back contacts activated by RTA reduce the time and temperature of treatment.•Photovoltaic parameters and their dispersion studied by multiple back contact samples.•RTA on CuxTe/Au back contacts enhance PV parameters and reduce their dispersion.•The presence of the Cu1·85Te phase (uncommon) after RTA on CuxTe/Au back contacts.