A WSe2/MoSe2 heterostructure photovoltaic device

We report on the photovoltaic effect in a WSe2/MoSe2 heterojunction, demonstrating gate tunable current rectification with on/off ratios of over 104. Spatially resolved photocurrent maps show the photovoltaic effect to originate from the entire overlap region. Compared to WSe2/MoS2 heterostructures, our devices perform better at long wavelengths and yield higher quantum efficiencies, in agreement with Shockley-Queisser theory.