You might take a look at the following paper on SB extraction for 2D material contacts.
Schottky barrier lowering due to interface states in 2D heterophase devices
By: Jelver, Line; Stradi, Daniele; Stokbro, Kurt; et al.
NANOSCALE ADVANCES Volume: 3 Issue: 2 Pages: 567-574 Published: JAN 21 2021
In principle, you might just do bulk calculation, obtaining LDOS across the contact, using a new PDOS analysis object projecting on Sites. Hartree Difference Potential can then be used as well, in combination with LDOS analysis. Note that one does not get any bias dependence in this calculation, for that one needs to do device calcualtions.