Titanium oxide contact passivation layer for thin film crystalline silicon solar cells

摘要

Thin film crystalline silicon (c-Si) solar cells have been a hot topic of photovoltaic research recently because its lower material consumption could potentially lead to lower capital expenditure. However, contact recombination is more prominent in thin-film c-Si solar cells compared with it in traditional c-Si solar cells due to higher carrier concentration. To address such a challenge, this work presents a design of metal-insulator-semiconductor (MIS) contact, based on thin TiOx layer that is grown by atomic layer deposition (ALD). Transmission line measurement (TLM) was conducted to study the conducting behavior of the TiOx MIS contact structure. Experimental results demonstrate that with the same doping density in silicon, the TiOx MIS contact forms an Ohmic contact to n-type silicon with good conductivity while cannot form Ohmic contact with p-silicon. This result demonstrates that the ALD TiOx layer can conduct electrons while blocking holes, thereby potentially reduce the contact recombination for thin-film c-Si solar cells, leading to an improvement of cell efficiency.