A semiconductor hetero-structure exhibiting photovoltaic effect was grown by a combination of sequential ionic layer adsorption reaction and chemical spray pyrolysis technique. The forward current voltage characteristic of the device showed a dynamic negative resistance region. It was observed that the onset of the dynamic negative resistance can be tuned by the illumination intensity of the incident light. Low temperature electrical studies of the device showed the presence of shallow states at similar to 80 meV and similar to 15 meV in the band structure. Work function measurement using Kelvin Probe proved the presence of inverted bands in this hetero structure. Shallow states trapped within these bands may be responsible for the negative resistance exhibited by the hetero-structure. (C) 2015 Elsevier B.V. All rights reserved.