What are the oxidation states of galium and arsenic in GaAs semiconductor?
In general, gallium can have +1 and +3 oxidation states, though +1 is a very rare condition. In its turn arsenic possible oxidation states are -3, +3 and +5. As it is stated in Wikipedia, gallium oxidation state in gallium arsenide is +3. Once again, arsenic has -3 oxidation state in arsenides or intermetallic compounds. Therefore, gallium arsenide oxidation states are +3 for Ga and -3 for As. This is logical because the electronegativity of As is higher then Ga. As for Simon Sze, he is an electrical engineer and physicist and not a chemist. From the mathematical point of view (-3)(+3) is the same thing as (-1)(+1).