Description of field of research:

This project aims to passivate the material defects in the Si1-xGex solar cell grown on silicon substrates using advanced hydrogenation techniques incorporating minority carrier injection. This will provide a better platform with improved quality for the III-V solar cell growth, and eventually improve the efficiency of the tandem solar cells grown on silicon substrates. 

III-V solar cells grown on silicon substrates are promising candidates for tandem structures due to the high efficiency of the III-V solar cells and low cost of the silicon substrate. However, a remaining key challenge is the lattice mismatch between III-V material and silicon. High quality Si1-xGex layers have been demonstrated to be an ideal material to realise lattice constant transition in monolithic III-V on Si tandem structures, and previous work at UNSW has shown the improvement of SiGe solar cells using variations of the hydrogenation process. This project will study the impact of hydrogenation on Si1-xGex solar cells grown on silicon substrates and develop hydrogen plasma process to improve the efficiency of the Si1-xGex solar cell to provide a high-quality platform for further tandem solar cell growth.


Photovoltaic and Renewable Energy Engineering

Research areas

Hydrogen plasma, defects passivation, silicon germanium solar cells

The school offers not only world class facilities for solar cell design, fabrication and characterisation but it is also teaming with world renowned researchers and dozens of PhD students always eager to share their knowledge and experience. The student will work closely with supervisor Dr. Li Wang who is an ACAP research fellow, co-supervisor 3rd year PhD candidate Zhenyu Sun who has intensive experiences in solar cell fabrication and characterisation, and obtain great support from A. Prof Brett Hallam who is one of the commercialised hydrogenation technology inventors. Their research background relates closely to the project where they can guide the student's work in both experimental and theoretical areas.

The student undertaking this project will learn solar cell fabrication process, have access to hydrogen plasma tool and characterise solar cells including I-V measurement, EQE and reflection measurements. The student will also learn design of experiment and data analysis to potentially improve the hydrogenation passivation process and generate new ideas. All of these form the basis of research components and will be benefit students' thesis, PhD study and other research related activities. The outputs of this research will lead to potential journal/conference publications.

  • Kar S , Pankove J I , Tsuo Y S . Remote plasma hydrogenation of ion beam amorphized silicon[J]. Applied Physics Letters, 1991, 59(6):718.