Design and Analysis of Novel Ge-GeTe PN Junction for Photovoltaics
Institute of Electrical and Electronic Engineers (IEEE)
2016 IEEE National Aerospace and Electronics Conference (NAECON) and Ohio Innovation Summit (OIS)
The continuing rise in demand for energy places a similarly increasing demand to improve power production methods and efficiency. In regards to solar power generation, one major limiting factor with existing photovoltaic (PV) systems is the management of heat produced and photon interactions with the PV device. Typical devices operate within the 300-1000 nm range of the solar spectrum, greatly limiting the range of photons used for power generation. Furthermore, since infrared light (<;1200nm) incident upon Silicon PV devices are not utilized in electron-hole pair creation, the device temperature immediately increases during operation. Due to these factors, a novel approach was pursued to develop a more efficient single crystalline PV cell. Fabrication of the device began with an antimony (Sb) doped germanium (Ge) wafer, followed by a thin film (i.e. 200nm) of amorphous germanium telluride (a-GeTe) deposited using RF sputtering. Utilizing the chalcogenide phase change (PC) characteristics of a-GeTe, the wafer was transitioned at 400°C for the 200nm deposited film, crystallizing the a-GeTe forming crystalline germanium telluride (c-GeTe). The device was annealed at 650°C activating the junction. Initial results show promise and indicate methods in which improvements can be made. The goal of this study was to identify materials and processes available to develop a low band gap PV cell responsive light ranging from blue to near infra-red (NIR) region.