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Development of arsenic doped Cd(Se,Te) absorbers by MOCVD for thin film solar cells
journal contributionposted on 16.08.2021, 14:11 by O Oklobia, G Kartopu, S Jones, P Siderfin, B Grew, HKH Lee, WC Tsoi, Ali AbbasAli Abbas, Michael WallsMichael Walls, DL McGott, MO Reese, SJC Irvine
Recent developments in CdTe solar cell technology have included the incorporation of ternary alloy Cd(Se,Te) in the devices. CdTe absorber band gap grading due to Se alloying contributes to current density enhancement and can result in device performance improvement. Here we report Cd(Se,Te) polycrystalline thin films grown by a chamberless inline atmospheric pressure metal organic chemical vapour deposition technique, with subsequent incorporation in CdTe solar cells. The compositional dependence of the crystal structure and optical properties of Cd(Se,Te) are examined. Selenium graded Cd(Se,Te)/CdTe absorber structure in devices are demonstrated using either a single CdSe layer or CdSe/Cd(Se,Te) bilayer (with or without As doping in the Cd(Se,Te) layer). Cross-sectional TEM/EDS, photoluminescence spectra and secondary ion mass spectroscopy analysis confirmed the formation of a graded Se profile toward the back contact with a diffusion length of ∼1.5 μm and revealed back-diffusion of Group V (As) dopants from the CdTe layer into Cd(Se,Te) grains. Due to the strong Se/Te interdiffusion, CdSe in the Se bilayer configuration was unable to form an n-type emitter layer in processed devices. In situ As doping of the Cd(Se,Te) layer benefited the device junction quality with current density reaching 28.3 mA/cm 2 . The results provide useful insights for the optimisation of Cd(Se,Te)/CdTe solar cells.
European Regional Development Fund (ERDF) and the Welsh European Funding Office (WEFO) for funding the 2nd Solar Photovoltaic Academic Research Consortium (SPARC II)
SPECIFIC IKC Phase 2
Engineering and Physical Sciences Research CouncilFind out more...
Innovate UK (920036)
European Regional Development Fund (c80892)
U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Office under contract number 34353
U.S. Department of Defence Office of Naval Research under contract number IAG-16-02002
- Mechanical, Electrical and Manufacturing Engineering
- Centre for Renewable Energy Systems Technology (CREST)