Faculty of Physics - University of Bucharest

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FACULTY OF PHYSICS

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2024-11-22 2:04

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Conference: Bucharest University Faculty of Physics 2018 Meeting

Section: Solid State Physics and Materials Science

Title:

Fabrication and characterization of Cu nanowire arrays for photovoltaic applications

Authors:

Ana-Maria PANAITESCU (1), Sorina IFTIMIE (1), Ștefan ANTOHE (1,2), Lucian ION (1), Adrian RADU (1), Vlad-Andrei ANTOHE (1,3)

Affiliation:

1) Research and Development Center for Materials and Electronic & Optoelectronic Devices (MDEO), Faculty of Physics, University of Bucharest, 077125 Bucharest-Măgurele, Romania

2) Academy of Romanian Scientists, 54 Splaiul Independenței, 0505094 Bucharest, Romania

3) Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain (UCL), B-1348 Louvain-la-Neuve, Belgium

E-mail

vlad.antohe@fizica.unibuc.ro

Keywords:

Nanostructured back-electrodes; Vertically-aligned copper (Cu) nanowires (NWs); Electrochemical synthesis within nanoporous anodic aluminum oxide (alumina) templates; Solar cells

Abstract:

Solar energy has great potential to cover society needs in the context of energy crisis the world is facing today. This is however achievable mainly through seeking reliable and low-cost fabrication methods for highly-performant photovoltaic devices. In this work, nanostructured collector electrodes have been designed to increase the solar cells' efficiency. In particular, back-contacts relying on large and dense arrays of vertically-aligned copper (Cu) nanowires (NWs) have been fabricated to considerably enlarge the collector surface of the photogenerated carriers, thus to improve the charge collection efficiency in future photovoltaic applications. The Cu vertical NWs have been grown through an electrochemical synthesis within the nanopores of an anodic aluminum oxide (AAO) template. The proposed electrochemical preparation protocol is cost-effective, versatile and allows an easy control of the NWs aspect-ratio and density on the electrode' surface. The superficial morphology and geometrical parameters of the Cu NWs have been subsequently examined by scanning electron microscopy (SEM). Afterwards, a semiconducting CdTe layer has been deposited by vacuum thermal evaporation (VTE) on top of the previously prepared Cu NWs back-electrodes, in an attempt to investigate the capability of the inorganic CdTe film to entirely fill-in the gaps between the NWs, to secure thus a high-quality holes collector of the ensuing photovoltaic element. Additional optical characterizations allowed the calculation of the deposited CdTe thickness, ultimately confirmed by direct SEM measurements. However, our preliminary SEM observations show that the CdTe layer did not fully penetrate the space between NWs probably due to the high deposition rates associated with the VTE process, pointing out that further processing optimizations are necessary. Although still in the beginning, the obtained results are promising and the related work deserves consideration in the future, as it may allow production of affordable and more efficient solar cells.