Synthesis of ZnO/CZTS Hetero-Structure Junction by Sol–Gel Spin Coating Technique

Abstract

Pertaining to the optimal band alignment of ZnO and CZTS, the heterostructure was fabricated with CZTS as the absorber layer and ZnO being the buffer layer coated on the FTO glass for photovoltaic application. Both the layers were deposited by using sol–gel spin coating technique. The results revealed the polycrystalline nature of both ZnO and CZTS films with distinct phase formations, with ZnO exhibiting prominent diffraction peaks at 31.77, 34.31, 36.20, 47.47, and 56.59° corresponding to (100), (002), (101), (102), and (110) planes, while CZTS showed diffraction peaks at (112), (220), and (312) planes. ZnO thin films demonstrated high optical transmittance (∼90%) and exhibited a wide band gap of 3.24 eV, while CZTS demonstrated a band gap of 1.44 eV. AFM images showed smooth surfaces with favorable topography for both films. Hall effect measurements indicated differences in electrical properties of the two films. Raman spectroscopy revealed vibrational energy patterns in both films. Additionally, current–voltage (I-V) characteristics revealed the electrical behavior of the ZnO/CZTS heterojunction, shedding light on its diode characteristics under both dark and illuminated conditions. With CZTS’s ideal band gap of 1.44 eV, sunlight is easily absorbed, and ZnO’s high electron mobility makes it an effective layer for electron transport. As a result, power conversion efficiency can be improved.

Keywords:

• CZTS
• Heterostructure
• Kesterite
• ZnO

Acknowledgements

Anuj Kumar would like to express gratitude to the Haryana State Council for Science Innovation and Technology under grant HSCSIT/R&D/2023/4283, and seed money grant by J. C. Bose University of Science and Technology YMCA, Faridabad, Haryana, India, for their financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Amanpal Singh is grateful to DST SERB, New Delhi, for the financial support provided for this study under grant [ECR/2017/003055].

Notes on contributors

Vinay Narwal

Vinay Narwal completed his BSc (physical sciences) fromthe University of Delhi, India in the year 2017. He obtained his MSc degree in applied physics from Amity University, Noida, India in the year 2023. Currently, he is pursuing his research work from the Department of Physics, JC Bose University of Science and Technology, Faridabad, India in the area of semiconductor thin film technology and characterization. E-mail: [email protected]

Damini Dalal

Damini received BSc (non medical) degree from Saraswati Mahila Mahavidyalaya College, MDU, Palwal, India in 2013 and MSc physics degree from Aggarwal College, MDU, Ballabgarh, India in 2015. She is currently pursuing PhD at the Department of Physics, Starex University, Gurugram, India in synthesis and characterization of earth-abundant materials based on thin film solar cells. E-mail: [email protected]

Amanpal Singh

Amanpal Singh received his PhD in electronic science from CEERI, Pilani, and Kurukshetra University, Kurukshetra, India in 2013. Since then, he has been focused on green energy harvesting and semiconductor thin films. He is currently working as assistant professor in the Department of Physics at theUniversity of Rajasthan, Jaipur, India. E-mail: [email protected]

Dinesh Kumar

Dinesh Kumar received his PhD (electronic materials & devices) from Cambridge University, U.K. in 1994 and has been working in the fabrication of semiconductor devices and thin films ever since. Currently, he is the acting vice-chancellor of Gurugram University, Gurugram, India. E-mail: [email protected].

Sanjay Kumar Swami

Sanjay Kumar Swami received his PhD from the Indian Institute of Technology Delhi, New Delhi in 2016. His research interests are in the areas of solar photovoltaics, and materials science. Currently, He is an associate professor at the Department of Physics, Dayananda Sagar University, Bengaluru, India. E-mail: [email protected]

Neha Chaturvedi

Neha Chaturvedi received her PhD from the Indian Institute of Technology Delhi, New Delhi in 2016. Her research expertise is organic solar cell and materials science. Currently, she is working at North Carolina State University, Raleigh NC, USA. E-mail: [email protected]

Manoj Kumar

Manoj Kumar received his PhD degree from the University of Delhi, Delhi in 2003 and has been working on semiconductor nanomaterials and devices. Currently, he is working as a professor, Department of Physics, Harcourt Butler Technical University (HBTU), Kanpur, India. Corresponding author. E-mail: [email protected]

Arvind Kumar

Arvind Kumar received PhD (physics) from IIT Roorkee, U.K. India in 2019 and has been working in the field of fabrication of thin film based electronic devices. Currently, he is working as an assistant professor, Department of Physics, Starex University, Gurugram, Haryana, India. E-mail: E-mail: [email protected]

Anuj Kumar

Anuj Kumar was awarded a PhD in microelectronics by Kurukshetra University, Kurukshetra, India in 2011. Subsequently, he worked as a research scientist at IIT Delhi for 8 years. Currently, he is an associate professor at JC Bose University of Science and Technology, Faridabad, India. E-mail: [email protected]