ERC Researchers Develop and Demonstrate High-Quality InGaN Films for Solar-Cell Applications

Achievement date: 
2014
Outcome/accomplishment: 

Researchers affiliated with the NSF-funded Engineering Research Center (ERC) for Quantum Energy and Sustainable Solar Technologies (QESST), which is headquartered at Arizona State University (ASU), have developed and demonstrated high-quality InGaN thin films with high In compositions and showing high optical properties.

Impact/benefits: 

This breakthrough should allow the production of high-quality InGaN for use in tandem solar cells. Additionally, the material’s thermal stability should allow high-temperature operations in concentrating solar-power technologies.

Explanation/Background: 

InGaN alloys are ideal for solar cells. Previous attempts to grow high-quality films with band gaps in the full solar-spectrum range have not been successful. However, collaborating teams from Georgia Tech and ASU developed and demonstrated realizable high-quality InGaN thin films. These films exhibit high optical properties that result from full-strain relaxation and uniform chemical-composition profiles in a range that was previously thought not possible. A detailed analysis at the nanometer scale indicates that films with In compositions greater than 60% (see figure) exhibit excellent structural and electronic properties, contrary to predictions of compositional In homogenities due to phase separation.