Structures and method for forming the same. The semiconductor structure comprises a photo diode that includes a first semiconductor region and a second semiconductor region. The first and second semiconductor regions are doped with a first and second doping polarities, respectively, and the first and second doping polarities are opposite. The semiconductor structure also comprises a transfer gate that comprises (i) a first extension region, (ii) a second extension region, and (iii) a floating diffusion region. The first and second extension regions are in direct physical contact with the photo diode and the floating diffusion region, respectively. The semiconductor structure further comprises a charge pushing region. The charge pushing region overlaps the first semiconductor region and does not overlap the floating diffusion region. The charge pushing region comprises a transparent and electrically conducting material.