Thin Film Photovoltaic Materials
Caltech People:
Prof. Harry Atwater (APh), Melissa Griggs, Brendan Kayes, Christine Richardson, Katsu Tanabe
Collaborators: Dr. Dan Aiken (Emcore), Dr. David Carlson (BP),
Dr. Richard King, Dr. Daniel Law (Spectrolab Inc.), Professor Nathan Lewis (Caltech)
Thin Film Photovoltaics Overview:
Photovoltaics(PV), the direct generation of electric power
from sunlight, is a technology which is currently enjoying
substantial growth and investment owing to rapid economic
growth in developing countries and growing worldwide public
sensitivity to the long-term importance of renewable energy
sources in industrialized countries as well. While there
are many possible options for photovoltaic materials and
devices, the key performance metric is the cost per Watt
of PV-generated electricity. Thus while photovoltaic solar
cells are semiconductor devices, the cost of device processing
per unit area must be several orders of magnitude less expensive
than typical microelectronics processing. As a result, while
most current solar cell manufacturing is done with crystalline
or multicrystalline silicon wafers, the future of photovoltaics
lies in development of inexpensive thin film devices and
processes, and current candidate materials include amorphous
silicon (a-Si), copper indium diselenide (CIS) and cadmium
telluride (CdTe).
Emerging Research Areas:
1. Crystalline Si Thin Films
Crystalline silicon thin films can exploit the wealth of
expertise in silicon processing, but use very thin films.
In this approach a crystalline silicon thin (1-30 microns)
film is grown on a inexpensive foreign substrate (e.g.,
glass, ceramic, steel) at low temperatures. Our strategy
is to devise crystal growth processes that enable large-grained
Si films to be produced at low process temperatures compatible
with low-cost substrates, such as glass
.
2. III-V Heterostructures
Currently the world's highest efficiency solar cells are
triple junction solar cells made with lattice-matched III-V
compound heterostructures. These structures require expensive
single crystal substrates and are currently too expensive
to be useful for large-scale terrestrial power applications,
although they are currently the technology of choice for
space power systems that provide onboard power for satellites,
unmanned and manned spacecraft. However, these challenges
may be overcome by use of wafer bonding and layer transfer
techniques to create nonlattice-matched heterostructures
on low-cost substrates, so we can enable new design freedoms
for tandem solar cells. This approach combined, with monolithic
microconcentrator optics, may enable ultrahigh efficiency
cells to enter the terrestrial photovoltaics arena.
Available Presentations:
III-V
Heterostructures for Ultrahigh Efficiency
Hot Wire
CVD for Photovoltaics
Available Publications:
10 µm minority-carrier diffusion lengths in Si wires synthesized by Cu-catalyzed vapor-liquid-solid growth Morgan C. Putnam, Daniel B. Turner-Evans, Michael D. Kelzenberg, Shannon W. Boettcher, Nathan S. Lewis, and Harry A. Atwater Applied Physics Letters (2009)
Increased cell efficiency in InGaAs solar cells with dielectric and metal back reflectors Koray Aydin, Marina S. Leite, and Harry A. Atwater Proceedings of the 34th IEEE PVSC (2009)
Predicted efficiency of Si wire array solar cells Michael Kelzenberg, Morgan Putnam, Daniel Turner-Evans, Nathan Lewis, Harry Atwater Proceedings of the 34th IEEE PVSC (2009)
GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer, Daniel C. Law, Shoghig Mesropian, Moran Haddad, Christopher M. Fetzer, Arthur C. Ackerman, Corinne Ladous, Richard R. King, and Harry A. Atwater Applied Physics Letters (2008)
Improved electrical properties of wafer-bonded p-GaAs/n-InP interfaces with sulfide passivation Keisuke Nakayama, Katsuaki Tanabe, and Harry A. Atwater Journal of Applied Physics (2008)
Photovoltaic Measurements in Single-Nanowire Silicon Solar Cells Michael D. Kelzenberg, Daniel B. Turner-Evans, Brendan M. Kayes, Michael A. Filler, Morgan C. Putnam, Nathan S. Lewis, and Harry A. Atwater Nano Letters (2008)
Plasmonic Nanostructure Design for Efficient Light Coupling into Solar Cells Vivian E. Ferry, Luke A. Sweatlock, Domenico Pacifici, and Harry A. Atwater Nano Letters (2008)
Single-Nanowire Si Solar Cells Michael D. Kelzenberg, Michael A. Filler, Brendan M. Kayes, Morgan C. Putnam, Daniel B. Turner-Evans, Nathan S. Lewis, Harry A. Atwater Proceedings of the 33rd IEEE PVSC (2008)
High efficiency InGaAs solar cells on Si by InP layer transfer James M. Zahler, Katsuaki Tanabe, Corinne Ladous, Tom Pinnington, Frederick D. Newman, and Harry A. Atwater Applied Physics Letters (2007)
Role of hydrogen in hydrogen-induced layer exfoliation of germanium James M. Zahler, Anna Fontcuberta i Morral, Melissa J. Griggs, Harry A. Atwater, Yves J. Chabal Physics Review B (2007)
Design Approaches and Materials Processes for Ultra-high Efficiency Lattice Mismatched Multi-Junction Solar Cells Melissa J. Griggs, Daniel C. Law, Richard R. King, Arthur C. Ackerman, James M. Zahler, and Harry A. Atwater Proc. of 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion (2006)
Direct-bonded GaAs/InGaAs tandem solar cell Katsuaki Tanabe, Daniel J. Aiken, Mark W. Wanlass, Anna Fontcuberta i Morral and Harry A. Atwater Applied Physics Letters (2006)
Microsecond minority carrier lifetimes in HWCVD-grown films and implications for thin film solar cells Maribeth S. Mason, Christine E. Richardson, Harry A. Atwater, R. K. Ahrenkiel Thin Solid Films (2006)
p-n Junction Heterostructure Device Physics Model of a Four Junction Solar Cell Melissa J. Griggs, Brendan M. Kayes, and Harry A. Atwater Proc. of SPIE Vol. 6339 (2006)
Synthesis and Characterization of Silicon Nanorod Arrays for Solar Cell Applications Brendan M. Kayes, Joshua M. Spurgeon, Thomas C. Sadler, Nathan S. Lewis, Harry A. Atwater IEEE 4th World Conference on Photovoltaic Energy Conversion Proceedings (2006)
A Phase Diagram for Morphology and Properties of Low Temperature Deposited Polycrystalline Silicon Grown by Hot-wire Chemical Vapor Deposition Christine E. Richardson, Maribeth S. Mason, and Harry A. Atwater IEEE Proceedings (2005)
A Phase Diagram of Low Temperature Epitaxial Silicon Grown by Hot-wire Chemical Vapor Deposition for Photovoltaic Devices Christine E. Richardson, Brendan M. Kayes, Matthew J. Dicken, Harry A. Atwater Proceedings of MRS Spring Meeting (2005)
Comparison of the device physics principles of planar and radial p-n junction nanorod solar cells Brendan M. Kayes, Nathan S. Lewis, and Harry A. Atwater Journal of Applied Physics (2005)
Radial pn junction nanorod solar cells: device physics principles and routes to fabrication in silicon Brendan M. Kayes, Christine E. Richardson, Nathan S. Lewis, Harry A. Atwater IEEE Proceedings (2005)
Spectroscopic studies of the mechanism for hydrogen-induced exfoliation of InP Anna Fontcuberta i Morral, James M. Zahler, Melissa J. Griggs, Harry A. Atwater, and Yves J. Chabal Physical Review B (2005)
Quantitative modelling of nucleation kinetics in experiments for poly-Si growth on SiO2 by hot wire chemical vapor deposition Maribeth S. Mason, Jason K. Holt, and Harry A. Atwater Thin Solid Films (2004)
Hot-wire chemical vapor deposition for epitaxial silicon growth on large grained polycrystalline silicon templates Maribeth S. Mason, Claudine M. Chen, Harry A. Atwater Thin Solid Films (2003)
Hot-wire chemical vapor deposition of high hydrogen content silicon nitride for solar cell passivation and anti-reflection coating applications Jason K. Holt, David G. Goodwin, A.M. Gabor, F. Jiang, M. Stavola, Harry A. Atwater Thin Solid Films (2003)
InGaAs/InP double heterostructures on InP/Si templates fabricated by wafer bonding and hydrogen-induced exfoliation Anna Fontcuberta i Morral, James M. Zahler, Harry A. Atwater, S. P. Ahrenkiel, and Mark W. Wanlass Applied Physics Letters (2003)
The aging of tungsten filaments and its effect on wire surface kinetics in hot-wire chemical vapor deposition Jason K. Holt, Maribeth Swiatek, David G. Goodwin, and Harry A. Atwater Journal of Applied Physics (2002)
Gas phase and surface kinetic processes in polycrystalline silicon hot-wire chemical vapor deposition Jason K. Holt, Maribeth Swiatek, David G. Goodwin, R.P. Muller, William A. Goddard III, Harry A. Atwater Thin Solid Films (2001) |