  ZnO doped with Gallium (Ga3+) demonstrates better crystalline nature and
conductivity increases. Latent defect states are suppressed. However, due to
the larger charge of Ga3+ oxygen interstitials are generated which control the
sensing speed. The conductance increases as a consequence of reduced defect
states, especially the oxygen vacancies. The photocurrent increases with Galium
incorporation, but a more intense increase in the current reduces the
sensitivity.
