Thin Film WSe 2 for Use as a Photovoltaic Absorber Material

An excellent candidate for an earth abundant absorber material is WSe 2 which can be directly grown as a p-type semiconductor with a band gap near 1.4 eV. In this work we present the structural, optical, and electrical properties of thin film WSe 2 grown via the selenization of sputter deposited tungsten films. We will show that highly textured films with an optical band gap in range of 1.4 eV, and absorption coefficients greater than 10 5 /cm across the visible spectrum can be easily achieved. In addition we will present Hall Effect and carrier density measurements as well, where will show densities in the 10 17 cm -3 range and p-type Hall mobilities greater than 10 cm 2 /V-s range can be obtained. We employ these results to numerically simulate solar cells based on this material, where we will show efficiencies greater than 20% are possible.

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