Initiation of Research in Engineering Science through Optical and Electronic Characterization of Polycrystalline Si Semiconductor Wafers for Use in PV

Faculty #46
Discipline: Physics
Subcategory: STEM Research

Andriy V. Semychayevskyy - Lincoln University
Co-Author(s): Harley T. Johnson, UIUC, Urbana, IL

This HBCU-UP RIA award’s main objective is to initiate the PI’s research on the structure-property relationships in semiconductor materials for photovoltaic solar cells working under different levels of incident light. This project is also meant to assist us in setting up our new Engineering Science program and in involving some of the current students in research. Dislocations and other defects in silicon and other electronic materials affect electronic transport properties, including carrier recombination rates and spatial distribution of carrier occupancy statistics. The carrier scattering and recombination processes affect the carrier dynamics in solar cells, and one of the interesting cases is the change in the electrical characteristics of PV solar cells when the photon flux density is varied. Until recently, most of the analysis used properties of bulk semiconductors to model carrier dynamics without any reference to the spatial distribution of defects or related electronic material properties. Modern characterization techniques, including spatially-resolved photoluminescence and photoelasticity can be used to deduce both the defect structure and the spatial distribution of carrier occupancies. Our collaborators at the University of Illinois at Urbana-Champaign have produced a large number of IR transmission and PL images for polycrystalline Si wafers as a part of another NSF-sponsored research project (GOALI). These images will be used to generate input parameters for our carrier transport models. Three undergraduate minority students (Engineering, Computer Science, and Physics majors) have been hired to work on this HBCU-UP RIA project in November of 2015 to perform optical and electrical characterization of semiconductor wafers and also to do data analysis (image processing of PL images using Matlab). At the moment we have preliminary data that reveal the problem of photovoltaic conversion efficiency degradation at higher illumination densities, and we are working on the interpretation of the spatially-resolved PL images obtained from our collaborators. The PI has also been developing multiphysics models of carrier transport in polycrystalline semiconductors with spatially resolved electronic properties.

Funder Acknowledgement(s): NSF-HBCUUP-RIA, Award 1505377

Faculty Advisor: None Listed,