Wideband Back-Illuminated Electromagnetic Radiation Detectors

An electromagnetic radiation detection system, comprising:

• a substrate;
• on a first surface of the substrate,
• a first electromagnetic radiation absorber;
• a second electromagnetic radiation absorber;
• and
• a buffer positioned between the first and second electromagnetic radiation absorbers;
• a first electromagnetic radiation emitter;
• a second electromagnetic radiation emitter;
• and
• a detection circuit configured to operate the first and second electromagnetic radiation emitters, and to separately detect,
• first electromagnetic radiation emitted by the first electromagnetic radiation emitter by reading a first current generated by the first electromagnetic radiation absorber;
• and
• second electromagnetic radiation emitted by the second electromagnetic radiation emitter by reading a second current generated by the second electromagnetic radiation absorber.

An electronic device, comprising:

• a housing;
• an electromagnetic radiation emitter configured to emit electromagnetic radiation through the housing;
• and
• an electromagnetic radiation detector configured to receive electromagnetic radiation returned from a target;
• wherein,
• the electromagnetic radiation detector includes,
• a substrate having a first surface opposite a second surface;
• a first electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths;
• a buffer stacked on the first electromagnetic radiation absorber and configured to absorb at least some of the first set of electromagnetic radiation wavelengths;
• and
• a second electromagnetic radiation absorber stacked on the buffer and configured to absorb a second set of electromagnetic radiation wavelengths;
• wherein,
• the second set of electromagnetic radiation wavelengths includes at least some electromagnetic radiation wavelengths that are not in the first set of electromagnetic radiation wavelengths.