Graded bandgap photodetector

摘要: The invention is a reduced noise avalanche photodetector. detector comprises p-type region, an n-type and graded bandgap region situated between the p- regions. Radiation to be detected absorbed in one of regions charge carriers are generated response thereto. When device under reverse bias, type photogenerated carrier injected by diffusion into initiates discharge therein. initiating moves toward decreasing energy, while other increasing thus resulting large difference ionization coefficients two types carriers. differing "quasi-electric" fields experienced also contributes electrons holes.