EAGER: Engineering Defect Structure in Nanocrystalline Silicon: A Fundamental Study Using Scanning Probe Microscopy

South Dakota State University, Brookings SD

Investigators

Abstract

The objective of this EArly-Concept Grant for Exploratory Research (EAGER) award is to elucidate the fundamental microscopic processes that are responsible for metastability in hydrogenated nanocrystalline Si (nc-Si:H). Hydrogenated nanocrystalline silicon (nc-Si:H) with improved optoelectronic properties is important for cost-effective photovoltaics and high-performance optoelectronic devices. However, the electrical properties of nc-Si:H produced using existing technologies degrade under light exposure (light induced degradation) due to the generation of metastable defects. The origin of the defects and their effect on light absorption and charge transport at the nanoscale has been under debate for a long time. The proposed study will utilize a unique combination of novel scanning probe microscopy-based optoelectronic characterization and first-principles simulation of charge transport through crystalline and amorphous regions to quantify the role of various microscopic processes underlying the metastability. If successful, this interdisciplinary collaborative effort will help develop highly stable nc-Si:H that can be incorporated into advanced solar cell designs. The proposed effort will encourage the participation of Native Americans into higher education. Native Americans represent about 8.5% of the population in South Dakota, and attracting this community into science and technology areas has been a challenge. SDSU's College of Engineering has developed an active outreach program to motivate Native American high-school students towards higher education (SDSU-Flandreau Indian School Success Academy). This project includes a workshop on solar energy for Native American high-school and middle-school students. A new graduate course in nanoscale imaging of PV materials will be developed, and multiple graduate and undergraduate courses will be enhanced.