Pixel structure

A method for forming a pixel structure, comprising:

• forming on a substrate, a diode device comprising:
• a diode body comprising a base portion protruding from the substrate and a main portion on top of the base portion, wherein a footprint of the base portion is smaller than a footprint of the main portion, and wherein the main portion comprises first and second oppositely doped regions formed in a top portion of the main portion, wherein the first doped region is formed in a central part of the footprint of the main portion and the second doped region is formed along a periphery of the footprint of the main portion;
• a gate arranged to circumferentially surround the diode body, wherein the gate comprises a first gate portion surrounding the main portion and a second gate portion protruding inwardly from the first gate portion to undercut the main portion and surround the base portion;
• and
• a gate dielectric layer arranged to separate the gate and the diode body;
• wherein the diode body is formed using a selective epitaxial growth process subsequent to forming the gate and the gate dielectric layer.