An international team of researchers have discovered an innovative tuning process that could enable a new semiconductor material to be used for solar cell applications.
Solar cell
Semiconductors are a critical component in electronics. They are widely used in many products, such as solar panels, phones, TVs and satellites. Conventional semiconductor materials are made using expensive, rare elements like gallium, indium and tellurium.
However, researchers from the University of Liverpool, Binghamton University, and the University of College London have produced a new semiconductor material using abundantly available elements, such as zinc and tin.
The focus of the study was on zinc tin nitride. Research groups worldwide have recently synthesized this compound, which uses inexpensive and abundantly available metals which can be easily found at mature recycling plants.
The innovative tuning process discovered by the team could potentially enable this compound to be used as a cost-effective alternative to the semiconductor materials presently utilized in solar cell applications.
An alloy's band gap determines its suitability as a semiconductor. It had previously been believed that the band gap of the compound was too large to allow it to be used in solar cells and other applications. In this study, the researchers discovered that they could tune the band gap of the alloy using molecular beam epitaxy. This method introduced randomly distributed zinc and tin atoms to create disorder.
Dr Tim Veal, a reader in Physics and researcher in the University of Liverpool’s Stephenson Institute for Renewable Energy, said: “Such tuneability is typically achieved in other material systems by alloying, or blending in other elements, to obtain the desired result, However, this is not necessary with ZnSnN2, given the recent discovery.”
Dr Steve Durbin, Professor and Chair of Electrical and Computer Engineering at Western Michigan University, added: “We use a sophisticated crystal growth technique known as molecular beam epitaxy. It allowed us to control crystal quality by carefully adjusting parameters such as temperature and the ratio of incident atomic (or molecular) beams.”
Dr Veal added: “By doing so, the team has been able to observe a wide range of disorder in a number of samples, and correlated this with a significant reduction in band gap energy – paving the way for this material to be considered for solar cell applications.”
The UK Engineering and Physical Science Research Council and the US National Science Foundation, provided funding for this study.
The researchers have published this study paper in the journal, Advanced Energy Materials.