It was brought to my attention that Finland-based image sensor company Pixpolar offers IP of its "patented MIG (Modified Internal Gate) image sensor". The company promises "at least 60% higher resolution with same chip size compared to cameras with conventional CMOS/CCD image sensors" or "at least 50% smaller camera size compared to conventional technologies" at the same resolution.
Pixpolar web site has a description of its idea and simulation results. The sensor relies on a potential well created by a special doping. A photogenerated charge in this potential well modulates the drain current of the MOSFETs above it.
The company appears to be an incubator project started in May 2006.