Single crystalline GaSe/WSe2 heterointerfaces grown by van der Waals epitaxy. II. Junction characterization

The junction properties of GaSe/WSe2 heterointerfaces grown by van der Waals epitaxy have been characterized by photoelectron spectroscopy and surface photovoltage measurements (SPV). The surfaces of p-WSe2 substrates doped with Se excess convert to n doping during annealing at T≥720 K, leading to a SPV of 330 mV. Deposited p GaSe forms an n-p heterodiode opposing the p-n homodiode within the substrate. Promising results are obtained for n-WSe2/p-GaSe heterointerfaces with SPV of at least 0.3 eV. The valence band and conduction band offsets are 0.6 and 0.2±0.1 eV, respectively, in accordance with the Anderson model of heterojunction formation.