Wong, JoesonJariwala, DeepTagliabue, GiuliaTat, KevinDavoyan, Artur R.Sherrott, Michelle C.Atwater, Harry A.2019-05-092019-05-092019-05-09201710.1021/acsnano.7b03148https://infoscience.epfl.ch/handle/20.500.14299/156342We report experimental measurements for ultrathin (<15 nm) van der Waals heterostructures exhibiting external quantum efficiencies exceeding 50% and show that these structures can achieve experimental absorbance >90%. By coupling electromagnetic simulations and experimental measurements, we show that pn WSe2/MoS2 heterojunctions with vertical carrier collection can have internal photocarrier collection efficiencies exceeding 70%.HeterojunctionHigh efficiencyMoS2PhotovoltaicsQuantum efficiencyVan der WaalsWSe2text::journal::journal article::research article