Amorphous silicon PEC-PV hybrid structure for photo-electrochemical water splitting

Abstract

The paper presents fabrication and characterization of amorphous silicon carbide (a-SiC:H) based structures for photo-electrochemical (PEC) water splitting. The increase of the photocurrent of PEC upon the decreased of CH4 flow during the deposition is associated with the decrease of the band gap and increased absorption of light in a-SiC:H. Photocurrent of 50 μA/cm2 is achieved for PEC structure prepared with the lowest CH4 flow during the deposition. An ITO/a-SiC:H/Si silicon heterojunction structure forming a simple photovoltaic cell (PV) with efficiency of 9.66% was prepared to support additional voltage hereby forming a hybrid PEC-PV system. ASA simulation revealed that a photocurrent of 0.62 mA/cm2 and solar to hydrogen efficiency of 0.76% can be achieved for hybrid a PEC-PV structure with 5 PVs connected in series behind the PEC cell. Further opportunities for increasing the performance are discussed and summarized.