Method of making an optical detector

A method of making an array of photodetectors responsive to incident light, the method comprising:

• forming a substrate of a material which is transparent to said incident light which, in use, impinges a first major surface of said substrate;
• forming the array of photodetectors wherein each photodetector in said array is formed by:
• forming a plurality of multiple discrete first regions of a first optical material on or adjacent a second major surface of said substrate, each discrete first region having a geometric shape which it shares in common with the other discrete first regions of the first optical material, the common geometric shape having sloping sidewalls which angle towards a tip of said common geometric shape;
• forming a second region of a second optical material which is disposed as a unitary region between each of the plurality of multiple discrete first regions of the first optical material and the substrate, the second optical material absorbing light of a shorter wavelength than light absorbed by the multiple discrete absorber regions of the first optical material;
• forming a metal reflector and contact layer which contacts or adjoins the tips of the multiple discrete regions of the first optical material, and
• disposing a barrier between the each of the plurality of multiple discrete regions of the first optical material and the second region of the second optical material, said barrier having an electronic band structure that passes minority carriers of the at least the second optical material but that blocks the majority carriers of both the first and second optical materials.

A method of making an array of photodetectors responsive to incident light, the method comprising:

• forming a substrate of a material which is transparent to said incident light which, in use, impinges a first major surface of said substrate;
• forming the array of photodetectors wherein each photodetector in said array is formed by:
• forming a plurality of multiple discrete regions of a first optical material, each discrete region having a geometric shape which it shares in common with the other discrete regions of the first optical material, the common geometric shape having sloping sidewalls which angle towards a tip of said common geometric shape, said plurality of multiple discrete regions of the first optical material being disposed on or adjacent a second major surface of said substrate;
• forming a common integral body of a second optical material which is disposed between the plurality of multiple discrete regions of the first optical material and the substrate, the second optical material absorbing light of given wavelengths, the first optical material being essentially transparent to said given wavelengths;
• forming a separate metal reflector and contact layer which contacts or adjoins the tips of the multiple discrete regions of the first optical material;
• and
• disposing a barrier between the each of the plurality of multiple discrete regions of the first optical material and the second optical material, said barrier having an electronic band structure that passes minority carriers of the second optical material but that blocks the majority carriers of the second optical material.