ITO is included in the material as conductor in Silvaco. If you are taking ITO as contact then you should define its work function in the contact statement.
Surprisingly ITO is categorized as insulator for ATHENA and conductor for ATLAS. If you want to have a layer of ITO on glass then one trick is to use "deposit" command in ATHENA to deposit a conductor (e.g. Gold) on your glass then switch to ATLAS and use "region num=# modify material=ITO" to change Gold layer into ITO (# is the number of deposited Gold region).
Im simulating thin film solar cells and I would like to add a metal layer different from contact electrode. i added a conductor region but I don't know how to introduce the work function of the metal to simulate different metals. Or may be another way to define a metal layer.