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DOE OSTI · 3484939

CdTe‐Based Solar Cells with Variations in Mg Concentration in the MgZnO Emitter

Pandey, Ramesh·Munshi, Amit·Shimpi, Tushar·Shah, Akash·Bothwell, Alexandra·Kuciauskas, Darius·Sites, James R.
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Abstract

The optimal fraction of Mg incorporation in sputter-deposited Mg X Zn 1−X O (MZO) emitters for thin-film CdTe-based solar cells is evaluated by varying it over a range of x from 0 to 0.35. This range allows a variation in the conduction band offset from −0.1 eV (cliff like) to +0.32 eV (spike like). Here, a maximum efficiency of 18.5% for cells with the bilayer CdSeTe/CdTe absorber occurs at x = 0.15, which corresponds to a spike-like band offset near 0.2 eV, as confirmed by X-ray photoelectron spectroscopy. In addition, good cell performance is seen over a fairly broad range of x extending from 0.1 to 0.25. The MZO optical bandgap increases with the Mg fraction, consistent with an increasing conduction band offset. Temperature-dependent current−voltage measurements and time-resolved photoluminescence show improvement in the emitter/absorber interface with the incorporation of Mg. Capacitance−voltage measurements show that the depletion region extends further into the absorber with more Mg, and X-ray diffraction confirms a change from a hexagonal-dominant crystal structure toward zinc blende at x = 0.35.

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14 SOLAR ENERGYCdTeMZOPhotovoltaicsSolar cellsThin filmsthin-film solar cells

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Pandey, Ramesh, Munshi, Amit, Shimpi, Tushar, Shah, Akash, Bothwell, Alexandra, Kuciauskas, Darius, Sites, James R.. 2021-04-21. CdTe‐Based Solar Cells with Variations in Mg Concentration in the MgZnO Emitter. https://doi.org/10.1002/solr.202100126

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