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

Miroslav Mikolasek – Martin Kemeny – Filip Chymo – Peter Ondrejka – Jozef Huran

   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.

Keywords: amorphous silicon, photo-electrochemical cell, hydrogen generation, PEC-PV hybrid system

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