US 12,249,666 B2
Use of a low bandgap absorber region in a laser power converter
Christopher M. Fetzer, Saugus, CA (US); and Dimitri D. Krut, Encino, CA (US)
Assigned to The Boeing Company, Arlington, VA (US)
Filed by The Boeing Company, Chicago, IL (US)
Filed on Dec. 11, 2018, as Appl. No. 16/216,449.
Prior Publication US 2020/0185559 A1, Jun. 11, 2020
Int. Cl. H01L 31/0687 (2012.01); H01L 31/0352 (2006.01); H01L 31/0725 (2012.01)
CPC H01L 31/06875 (2013.01) [H01L 31/035272 (2013.01); H01L 31/0725 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A device, comprising:
a laser power converter (LPC) comprised of a plurality of subcells on a substrate, the plurality of subcells including top and bottom subcells;
at least one of the plurality of subcells having an emitter and base with a low bandgap absorber region (LBAR) coupled between the emitter and base;
the emitter and base are comprised of a first material with a first bandgap higher than a wavelength of incident laser light, such that the emitter and base are transparent to the incident laser light and do not generate a current in response to the incident laser light, wherein the first material is AlGaAs with an Al content higher than a mole fraction of 10%, the first bandgap is higher than 1.55 eV, and the wavelength of the incident laser light is 808 nm;
the low bandgap absorber region is comprised of a second material with a second bandgap lower than the first bandgap, such that only the low bandgap absorber region absorbs the incident laser light and generates the current in response to the incident laser light, wherein the second material is Ga(In)As; and
the current generated between the top and bottom subcells is controlled with the second material and thickness of the low bandgap absorber region only, such that only the low bandgap absorber region is configured to balance the current generated between the top and bottom subcells, and the emitter and base are not thickness limited to balance the current generated between the top and bottom subcells.