The potential of textured front ZnO and flat TCO/metal back contact to improve optical absorption in thin Cu(In,Ga)Se2 solar cells
2007 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 15, 5968-5972 p.Article in journal (Refereed) Published
The role of additionally textured front transparent conductive oxide − TCO (ZnO:Al) and flat TCO/metal contact on optical improvements in thin Cu(In,Ga)Se2 (CIGS) solar cells are investigated by means of numerical simulations. A de-coupled analysis of two effects related to additional texturing of front surface of ZnO:Al TCO − (i) enhancement of light scattering and (ii) decreased total reflectance (antireflective effect) − reveals that the improvements in quantum efficiency, QE, and short-circuit current, JSC, of the solar cell originate from an antireflective effect only. In order to improve optical properties of the back contact the introduction of a TCO layer (undoped ZnO) between CIGS and back metal contact is investigated from the optical point of view. In addition to ZnO/Mo, a highly reflective ZnO/Ag contact (ZnO is also assumed to work as a protection layer for Ag) is also included in simulations. Results show significant increase in reflectance related to introduced ZnO in front of Mo. Drastically increased reflectance is obtained if ZnO/Mo is substituted with ZnO/Ag. The improvements in QE and JSC of a thin CIGS solar cell, related to ZnO/metal contacts are presented.
Place, publisher, year, edition, pages
2007. Vol. 515, no 15, 5968-5972 p.
CIGS solar cell, Light scattering, Optical modeling, Metal back contact
Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-10908DOI: 10.1016/j.tsf.2006.12.093ISI: 000246831600050OAI: oai:DiVA.org:uu-10908DiVA: diva2:38676