GaAs solar cells using monolithically integrated II-VI semiconductors for roughened surfaces

When sunlight interacts with a solar cell the light excites electrons in the cell which are collected as electricity. The solar cell operates more efficiently the longer the light interacts within the cell. This is accomplished by increasing the length of the path the light travels in the cell material. One way this is done is to make the solar cell thicker. Unfortunately, this increases the distance the electrons must travel to the contacts in the solar cell where they are collected allowing them more opportunity to recombine with the cell material. A solar cell is more efficient when it is made thinner, but allows light to travel a longer path in the cell material. Light trapping techniques are common in silicon based solar cells. However, this is more challenging for other material systems. To address this problem researchers at Arizona State University have developed a method for scattering light by attaching a layer to the back side of thin-film solar cells or other material systems. A roughened layer of ZnSe (zinc selenide) is deposited on the back of the cell. A reflective foil is then attached to the back of the ZnSe layer. This method increases solar cell efficiency because it increases the distance the light travels in the solar cell. Potential Applications Production of solar-grade silicon More energy-efficient refining of many industry metals such as aluminum and copper Benefits and Advantages Single-junction solar cells Multi-junction solar cells Infrared Detectors Original Download PDF For more information about the inventor(s) and their research, please see Dr. Yong-Hang Zhang's directory webpage