MONOLITHIC MULTIJUNCTION POWER CONVERTER
Resonant cavity power converters for converting radiation in the wavelength range from 1 micron to 1.55 micron are disclosed. The resonant cavity power converters can be formed from one or more lattice matched GaInNAsSb junctions and can include distributed Bragg reflectors and/or mirrored surfaces for increasing the power conversion efficiency.
1 . A multijunction power converter, comprising:
a thinned GaAs or Ge substrate;
a first semiconductor layer overlying the thinned GaAs or Ge substrate, wherein the first semiconductor layer does not absorb at a monochromatic wavelength, wherein the monochromatic wavelength is within a range from 1.3 micron to 1.55 micron;
a first GaInNAsSb junction on the first semiconductor layer, wherein the first GaInNAsSb junction has a bandgap configured to absorb at the monochromatic wavelength;
a first tunnel junction on the first GaInNAsSb junction;
a second GaInNAsSb junction on the first tunnel junction, wherein the second GaInNAsSb junction has the bandgap configured to absorb at the monochromatic wavelength;
a second semiconductor layer overlying the second GaInNAsSb junction, wherein the second semiconductor layer does not absorb at the monochromatic wavelength; and
a distributed bragg reflector overlying the thinned GaAs or Ge substrate, wherein the first semiconductor layer overlies the distributed bragg reflector, wherein the distributed bragg reflector comprises layers of GaAs and AlGaAs.
2 . The multijunction power converter of claim 1 , further comprising:
a second tunnel junction on the second GaInNAsSb junction; and
a third GaInNAsSb junction on the second tunnel junction, wherein the third GaInNAsSb junction has a bandgap configured to absorb at the monochromatic wavelength;
wherein the second semiconductor layer overlies the third GaInNAsSb junction.
3 . The multijunction power converter of claim 1 , wherein each of the first semiconductor layer and the second semiconductor layer comprises GaAs.
4 . The multijunction power converter of claim 1 , wherein the monochromatic wavelength is 1 . 32 microns.
5 . The multijunction power converter of claim 1 , wherein the multijunction power converter has a power conversion efficiency of at least 20% for an input power within a range from 0.6 W to 6 W.
6 . The multijunction power converter of claim 1 , further comprising:
a second distributed bragg reflector overlying the second semiconductor layer.
7 . The multijunction power converter of claim 6 , further comprising:
a heatsink bonded to the second distributed bragg reflector.
8 . The multijunction power converter of claim 6 , further comprising:
a lateral conducting layer underlying the second distributed bragg reflector.
9 . The multijunction power converter of claim 8 , wherein the lateral conducting layer overlies the first semiconductor layer and underlies a top contact.
10 . The multijunction power converter of claim 1 , further comprising:
a back mirror overlying the second semiconductor layer.
11 . The multijunction power converter of claim 10 , wherein the back mirror comprises gold or a gold/nickel alloy.
12 . The multijunction power converter of claim 1 , wherein the thinned GaAs or Ge substrate has a bandgap higher than the bandgap of the first GaInNAsSb junction and the second GaInNAsSb junction.
13 . The multijunction power converter of claim 1 , wherein the first GaInNAsSb junction or the second GaInNAsSb junction comprises Ga 1-x In x N y As 1-y-z Sb z , wherein:
0<x<0.24, 0.01<y<0.07, and 0.001<z<0.20;
0.02<x<0.24, 0.01<y<0.07, and 0.001<z<0.03;
0.02<x<0.18, 0.01<y<0.04, and 0.001<z<0.03;
0.08<x<0.18, 0.025<y<0.04, and 0.001<z<0.03; or
0.06<x<0.20, 0.02<y<0.05, and 0.005<z<0.02.
14 . The multijunction power converter of claim 1 , wherein the first tunnel junction or the second tunnel junction comprises Ga 1-x In x N y As 1-y-z Sb z , wherein:
0<x<0.18, 0.01<y<0.05, and 0.001<z<0.15;
0<x<0.18, 0.001<y<0.05, and 0.001<z<0.03;
0.02<x<0.18, 0.005<y<0.04, and 0.001<z<0.03;
0.04<x<0.18, 0.01<y<0.04, and 0.001<z<0.03;
0.06<x<0.18, 0.015<y<0.04, and 0.001<z<0.03; or
0.08<x<0.18, 0.025<y<0.04, and 0.001<z<0.03.
15 . The multijunction power converter of claim 1 , wherein the thinned GaAs or Ge substrate has a thickness less than 50 microns, from 150 microns to 250 microns, or from 175 microns to 225 microns.
16 . The multijunction power converter of claim 1 , wherein the first GaInNAsSb junction or the second GaInNAsSb junction has a thickness from 100 nm to 1 micron.
17 . The multijunction power converter of claim 1 , further comprising:
a lateral conducting layer overlying the distributed bragg reflector.
18 . The multijunction power converter of claim 17 , wherein the lateral conducting layer comprises GaAs.
19 . The multijunction power converter of claim 17 , wherein the lateral conducting layer underlies the first semiconductor layer and a back contact.
20 . The multijunction power converter of claim 1 , wherein a thickness of the multijunction power converter is between 1 micron to 10 microns.