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Light-trapping nanostructures in ultrathin GaAs solar cells : towards a record efficiency

De Lepinau, Romaric LU (2016) PHYM01 20161
Solid State Physics
Department of Physics
Abstract
Producing electrical power with photovoltaic solar panels is very attractive as the sun
constitutes an inexhaustible source of clean energy. However, in order to make it a better
alternative to other energy sources, its drawbacks must be addressed. In particular, scientific
research is very active to find technologies that increase the efficiency of the solar
cells, or decrease their cost. Reducing the thickness of thin-film solar cells would serve
this second objective by reducing the amount of material needed. It also paves the way
towards third-generation solar cells, e.g. nanowire solar cells, because the effective lighttrapping
techniques that are developed and implemented will be needed in those future
devices. This master’s... (More)
Producing electrical power with photovoltaic solar panels is very attractive as the sun
constitutes an inexhaustible source of clean energy. However, in order to make it a better
alternative to other energy sources, its drawbacks must be addressed. In particular, scientific
research is very active to find technologies that increase the efficiency of the solar
cells, or decrease their cost. Reducing the thickness of thin-film solar cells would serve
this second objective by reducing the amount of material needed. It also paves the way
towards third-generation solar cells, e.g. nanowire solar cells, because the effective lighttrapping
techniques that are developed and implemented will be needed in those future
devices. This master’s thesis aims at implementing a theory of multi-resonant absorption
to ultrathin GaAs solar cells. The absorption is based on resonant photonic and plasmonic
modes, excited via a periodically nanostructured mirror at the rear side of the cell. A
process for the fabrication of solar cells implementing such a nanostructured mirror was
developed, and solar cells with simpler designs have already been made, with a 200 nm
thick absorber. They have been characterized and exhibit quite high Fill-Factor (82 %)
and open-circuit voltage (1.03 V) that are not degraded after transfer on another substrate,
which is promising for the final cell. The short-circuit current exhibited a value
of 16.1 mA.cm-2 without anti-reflection coating, and with only a flat mirror at the rear
side. Based on numerical simulations it is supposed to increase by 8.5 mA.cm-2 with the
addition of an Anti-Reflection Coating (ARC) and with the nanostructured mirror. Taking
this contribution into account, we expect a short-circuit current of 24.6 mA.cm-2 and an
efficiency of 21 %, that have never been reached for such thin solar cells (200 nm). The
process development is still ongoing for this final design, and we look forward to complete
the fabrication of a device. (Less)
Popular Abstract
Reducing the solar cells thickness is a step forward towards cheap, highly efficient photovoltaic modules. In this project, an innovative light-trapping strategy has been adapted and developed, which shows promising simulation results.
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author
De Lepinau, Romaric LU
supervisor
organization
course
PHYM01 20161
year
type
H2 - Master's Degree (Two Years)
subject
keywords
solar cells, photovoltaics, 3-5, III-V, Gallium Arsenide, light-trapping, resonance, nanostructure, nano-imprint
language
English
additional info
The master thesis work was conducted at Laboratoire de Photonique et de Nanostructures’ (LPN), the photonics and nanostructures laboratory of the French national center for scientific Research (CNRS)
id
8885537
date added to LUP
2016-06-28 11:12:28
date last changed
2016-12-25 04:08:06
@misc{8885537,
  abstract     = {Producing electrical power with photovoltaic solar panels is very attractive as the sun
constitutes an inexhaustible source of clean energy. However, in order to make it a better
alternative to other energy sources, its drawbacks must be addressed. In particular, scientific
research is very active to find technologies that increase the efficiency of the solar
cells, or decrease their cost. Reducing the thickness of thin-film solar cells would serve
this second objective by reducing the amount of material needed. It also paves the way
towards third-generation solar cells, e.g. nanowire solar cells, because the effective lighttrapping
techniques that are developed and implemented will be needed in those future
devices. This master’s thesis aims at implementing a theory of multi-resonant absorption
to ultrathin GaAs solar cells. The absorption is based on resonant photonic and plasmonic
modes, excited via a periodically nanostructured mirror at the rear side of the cell. A
process for the fabrication of solar cells implementing such a nanostructured mirror was
developed, and solar cells with simpler designs have already been made, with a 200 nm
thick absorber. They have been characterized and exhibit quite high Fill-Factor (82 %)
and open-circuit voltage (1.03 V) that are not degraded after transfer on another substrate,
which is promising for the final cell. The short-circuit current exhibited a value
of 16.1 mA.cm-2 without anti-reflection coating, and with only a flat mirror at the rear
side. Based on numerical simulations it is supposed to increase by 8.5 mA.cm-2 with the
addition of an Anti-Reflection Coating (ARC) and with the nanostructured mirror. Taking
this contribution into account, we expect a short-circuit current of 24.6 mA.cm-2 and an
efficiency of 21 %, that have never been reached for such thin solar cells (200 nm). The
process development is still ongoing for this final design, and we look forward to complete
the fabrication of a device.},
  author       = {De Lepinau, Romaric},
  keyword      = {solar cells,photovoltaics,3-5,III-V,Gallium Arsenide,light-trapping,resonance,nanostructure,nano-imprint},
  language     = {eng},
  note         = {Student Paper},
  title        = {Light-trapping nanostructures in ultrathin GaAs solar cells : towards a record efficiency},
  year         = {2016},
}