Date of Award
Master of Science
Department of Electrical and Computer Engineering
Ronald A. Coutu, Jr, PhD.
Based on the previous development of the hybrid multi-junction silicon (HMJ-Si) solar cell, this work characterized the preceding design for the development of the hybrid multi-junction silicon germanium (HMJ-SiGe) solar cell. Seven focus areas were investigated: diffraction pattern generation, photon propagation, silicon diffusion processing, ohmic contacts, the distributed Bragg reflector (DBR), the Fresnel zone plate (FZP), and the germanium/germanium telluride (Ge/GeTe) pn-junction Diffraction patterns were theoretically examined, and contact grating design characterization for reflectance and transmittance properties was modeled using rigorous coupled wave analysis. An improved silicon diffusion process follower was developed, and theoretical study and experimental assessment were accomplished for appropriate ohmic contacts, the DBR, the FZP, and the Ge/GeTe pn-junction for incorporation into the HMJ-SiGe solar cell architecture. Results showed that minima locations are nonexistent, the ratio between the metal width and electrical contact spacing is vital, an interfacial layer is required for Fermi level de-pinning, the DBR can reject detrimental wavelengths, the FZP excessively prevents transmittance, and p-type GeTe can form a pn-junction on n-type germanium. With an average efficiency of 1.27%, the HMJ-SiGe solar cell demonstrated a capstone requirement of charging a capacitor to 2.5 VDC in 11 minutes to illuminate a light emitting diode.
DTIC Accession Number
Lohrman, Jimmy J., "Characterization for the Development of the Hybrid Multi-Junction Silicon Germanium Solar Cell" (2016). Theses and Dissertations. 312.