biography

Nanocrysllaine Silicon (nc-Si:H) and Nanocrystalline Silicongermanium (nc-SiGe:H) are important material for thin film solar cell application. Transport properties determine the overall

efficiency of the solar cell. Nc-SiGe is particularly interesting because of it lower bandgap for use in tandem cells. Through his PhD research work, Dr.Saripalli established ways to systematically measure diffusion length and minority carrier lifetime. Particularly, lifetime measurement was the first of its kind in literature for nc-Si:H and nc-SiGe:H. The typical values

of lifetime in nc-Si and nc-SiGe were found to be in the range of 300-600ns and 150-250ns respectively. Systematic measurement of lifetimes and defect densities in the same solar cell

devices enabled to establish that Shockley Read-Hall (SRH) recombination holds true in these nanocrystalline materials. The dependence of lifetime on temperature was also studied. The resulting curve has been explained based on recombination process in these materials. Through the temperature study the trap locations could be modeled. Overall, this research work enabled a better understanding of carrier transport mechanism and measuring fundamental properties that control the thin film solar cell performance.

Dr. Saripalli is presently employed full-time as a Member of Technical Staff in the Technology and Manufacturing Group (TMG) of Maxim Integrated, a leading producer of analog and mixed-signal integrated circuit (IC) products for use in automotive, industrial, medical, and mobile applications. He is one of the key members of the engineering team at the wafer fabrication plant of Maxim in Beaverton, OR and is responsible for ramping and improving yield on CMOS and bipolar technologies.