SINGLE-CRYSTALLINE GASE/WSE2 HETEROINTERFACES GROWN BY VAN-DER-WAALS EPITAXY .2. 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 greater-than-or-equal-to 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.