By Topic

New generation transparent LPCVD ZnO electrodes for enhanced photocurrent in micromorph solar cells and modules

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

11 Author(s)
Laura Ding ; IMT - PVLAB (EPFL), Neuchâtel, Switzerland ; Mathieu Boccard ; Gregory Bugnon ; Mustapha Benkhaira
more authors

Summary form only given: Polycrystalline ZnO:B deposited by low-pressure chemical vapor deposition (LPCVD) was proven as an efficient electrode material for thin film silicon solar cells application, thanks to high transparency, good electrical conductivity and strong light scattering via self-textured surface. However, high doping used to lower resistivity of ZnO films, induces free carrier absorption (FCA), detrimental to current generation in the bottom microcrystalline cell of a micromorph device. Here we describe optimized 2 μm thick LPCVD ZnO:B bilayers, combining of a thin nucleation layer, plus a bulk layer, having different doping levels. This arrangement in one growth-step enables a separate control of electrical and optical properties of the films. It promotes the growth of strongly light diffusive structures with enhanced electron mobility (~45cm2/Vs) and low electron density (~2×1019 cm-3). This results in low FCA and moderate sheet resistance, that should easily be lowered to <;20Ω/sq. In an industrially scalable process, the bilayers approach provides highly transparent electrodes, well adapted for the development of micromorph solar cells. Indeed, a micromorph device generates less Jsc than its two separate junctions, for a higher voltage, allowing thus the use of a more resistive electrode. The potential of such bilayer front electrodes for power improvement and cost reduction of industrial micromorph modules is currently tested at Oerlikon Solar. First experiments already show a very promising gain of 3Wp/module, compared to modules on standard doped LPCVD ZnO.

Published in:

Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE

Date of Conference:

19-24 June 2011