Reduction of Cu-rich interfacial layer and improvement of bulk CuO property through two-step sputtering for p-CuO/n-Si heterojunction solar cell

• Main Authors: Masudy-Panah, Saeid, Dalapati, Goutam Kumar, Radhakrishnan, K., Kumar, Avishek, Tan, Hui Ru
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Physics::Electricity and magnetism
• Online Access: https://hdl.handle.net/10356/105351; http://hdl.handle.net/10220/20677; http://dx.doi.org/10.1063/1.4893321
• Institution: Nanyang Technological University

Copper-rich interfacial-layer (Cu-rich IL) is formed during sputter deposition of cupric oxide (CuO) layer on silicon (Si). It has significant impact on the performance of p-CuO/n-Si heterojunction solar cells. In this report, CuO films deposited on Si at different RF-power levels using single and two-step RF-sputtering techniques and p-CuO/n-Si heterojunction solar cells have been investigated. Systematic characterization using XPS, AFM, XRD, Raman, and HR-TEM reveal that two-step RF-sputtering technique offers better crystal quality CuO film with thinner Cu-rich IL layer. Photovoltaic (PV) properties with an open-circuit voltage (Voc ) of 421 mV, short circuit current (Jsc ) of 4.5 mA/cm2, and a photocurrent of 8.3 mA/cm2 have been achieved for the cells prepared using two-step sputtering method, which are significantly higher than that for the solar cells fabricated using a single-step sputtering. The PV properties were further improved by depositing CuO films at higher working pressure with nitrogen doping. The efficiency of the best device achieved is approximately 1.21%, which is the highest value reported for p-CuO/n-Si heterojunction based solar cells.