High Optical Quality Polycrystalline Indium Phosphide Grown on Metal Substrates by MOCVD for Photovoltaic Applications

Maxwell Zheng

EECS Department
University of California, Berkeley
Technical Report No. UCB/EECS-2012-39
April 4, 2012

http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-39.pdf

III-V semiconductor solar cells have demonstrated the highest power conversion efficiencies to date. However, the cost of III-V solar cells has historically been too high to be practical outside of specialty applications. This stems from the cost of raw materials, need for a lattice-matched substrate for single-crystal growth, and complex epitaxial growth processes. To address these challenges, here, we explore the direct non-epitaxial growth of thin poly-crystalline films of III-Vs on metal substrates by using MOCVD. This method minimizes the amount of raw material used while utilizing a low cost substrate. Specifically, we focus on InP which is known to have a low surface recombination velocity of carriers, thereby, making it an ideal candidate for efficient poly-crystalline cells where surface/interface properties at the grain boundaries are critical. The grown InP films are 1-3 microns thick and are composed of micron-sized grains that generally extend from the surface to the Mo substrate. They exhibit similar photoluminescence peak widths and positions as single-crystalline InP, as well as excellent crystallinity as examined through TEM and XRD analysis. This work presents poly-InP as a promising absorber layer for future photovoltaics.

Advisor: Ali Javey


BibTeX citation:

@mastersthesis{Zheng:EECS-2012-39,
    Author = {Zheng, Maxwell},
    Title = {High Optical Quality Polycrystalline Indium Phosphide Grown on Metal Substrates by MOCVD for Photovoltaic Applications},
    School = {EECS Department, University of California, Berkeley},
    Year = {2012},
    Month = {Apr},
    URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-39.html},
    Number = {UCB/EECS-2012-39},
    Abstract = {III-V semiconductor solar cells have demonstrated the highest power conversion efficiencies to date. However, the cost of III-V solar cells has historically been too high to be practical outside of specialty applications. This stems from the cost of raw materials, need for a lattice-matched substrate for single-crystal growth, and complex epitaxial growth processes. To address these challenges, here, we explore the direct non-epitaxial growth of thin poly-crystalline films of III-Vs on metal substrates by using MOCVD. This method minimizes the amount of raw material used while utilizing a low cost substrate. Specifically, we focus on InP which is known to have a low surface recombination velocity of carriers, thereby, making it an ideal candidate for efficient poly-crystalline cells where surface/interface properties at the grain boundaries are critical. The grown InP films are 1-3 microns thick and are composed of micron-sized grains that generally extend from the surface to the Mo substrate. They exhibit similar photoluminescence peak widths and positions as single-crystalline InP, as well as excellent crystallinity as examined through TEM and XRD analysis. This work presents poly-InP as a promising absorber layer for future photovoltaics.}
}

EndNote citation:

%0 Thesis
%A Zheng, Maxwell
%T High Optical Quality Polycrystalline Indium Phosphide Grown on Metal Substrates by MOCVD for Photovoltaic Applications
%I EECS Department, University of California, Berkeley
%D 2012
%8 April 4
%@ UCB/EECS-2012-39
%U http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-39.html
%F Zheng:EECS-2012-39