Abstracts Book - IMRC 2018

• SC4-O016 Invited Talk
GaAs PHOTOVOLTAICS ON FLEXIBLE, INEXPENSIVE METAL
SUBSTRATES
Venkat Selvamanickam 1,2
1 University of Houston, Advanced Manufacturing Institute, Texas Center for Superconductivity,
United States. 2 University of Houston, Mechanical Engineering, United States.
By far, the highest solar cell efficiencies have been achieved with GaAs
photovoltaics (PV); still, their use has been limited by the high cost of GaAs
wafers. It is in this context that we are developing an innovative approach: a)
replace expensive wafers with inexpensive metal substrates and b) demonstrate
high efficiency thin film GaAs PV by roll-to-roll manufacturing. Single-crystallinelike
surfaces are needed for epitaxial growth of III-V compounds for highefficiency
PV. We have already developed such a substrate technology: singlecrystalline-like
Ge films on templates made by ion beam assisted deposition on
metal substrates. Epitaxial GaAs thin films have been grown on these Ge
templates by metal organic chemical vapor deposition (MOCVD). These epi GaAs
thin films show a grain-to-grain misorientation less than 1° and a strong
photoluminescence comparable to that of GaAs films on GaAs wafers. Electron
mobility above 1300 cm 2 /V-s and hole mobility above 100 cm 2 /V-s have been
achieved in GaAs:Si n-type and in GaAs:Zn p-type films on metal substrates.
Controlled doping has been obtained in GaAs:Si and GaAs:Zn films over a range
of 10 17 -10 19 cm -3 , necessary for the active device layers of solar cells.
Optimization of device architecture, passivation methods and antireflective
coating is ongoing to improve the efficiency of GaAs solar cells fabricated on
metal substrates. Conversion efficiencies above 10% have been achieved in
these flexible GaAs solar cells. Recent progress in fabrication and testing of thin
film GaAs solar cells on flexible metal substrates will be discussed in this
presentation.
Acknowledgment:
This work was supported partially by the U.S. Department of Energy SunShot
Initiative award DE-EE0006711
Keywords: gallium arsenide, flexible, epitaxy
Presenting authors email: selva@uh.edu