Diode barrier infrared detector devices and superlattice barrier structures

1. A diode barrier infrared detector device comprising:

a first contact layer;

an absorber layer adjacent to the first contact layer;

a barrier layer adjacent to the absorber layer, wherein the barrier layer comprises a diode structure formed by a p-n junction formed within the barrier layer; and

a second contact layer adjacent to the barrier layer, wherein the diode structure comprises:

an n-doped barrier layer adjacent to the absorber layer, the n-doped barrier layer comprising a first n-doped barrier region having a first doping level, a second n-doped barrier region having a second doping level, and a third n-doped barrier region having a third doping level, wherein:

the first n-doped barrier region is adjacent to the absorber layer;

the second n-doped barrier region is disposed between the first n-doped barrier region and the third n-doped barrier region;

the third doping level is greater than the second doping level; and

the second doping level is greater than the first doping level; and

a p-doped barrier layer disposed between the third n-doped barrier region of the n-doped barrier layer and the second contact layer, wherein the n-doped barrier layer has a thickness that is greater than a thickness of the p-doped barrier layer.

2. The diode barrier infrared detector device of claim 1 , wherein the barrier layer is such that there is substantially no barrier to minority carrier holes.

3. The diode barrier infrared detector device of claim 1 , wherein the p-n junction formed within the barrier layer is closer to the second contact layer than the absorber layer.

4. The diode barrier infrared detector device of claim 1 , wherein the absorber layer comprises an n-doped InAs/InAsSb superlattice structure, and the barrier layer comprises AlAsSb or AlGaAsSb.

5. The diode barrier infrared detector device of claim 1 , wherein a depletion region is contained entirely within the barrier layer.

6. The diode barrier infrared detector device of claim 1 , wherein:

a thickness of the first n-doped barrier region is greater than a thickness of the third n-doped barrier region; and

the thickness of the third n-doped barrier region is greater than a thickness of the second n-doped barrier region.

7. The diode barrier infrared detector device of claim 6 , wherein:

the first doping level is about 2.5×10 15 ;

the second doping level is about 6.0×10 16 ;

the third doping level is about 1.7×10 17 ; and

a doping level of the p-doped barrier layer is about 3.0×10 17 .

8. A superlattice barrier structure comprising a repeating sequence of an AlAs x Sb 1-x layer, a GaAs y Sb 1-y layer, and an InAs 1-z Sb z layer defining a superlattice structure, wherein:

0<x<1, 0<y<1, and 0<z<1;

the InAs 1-z Sb z layers are n-doped; and

the AlAs x Sb 1-x layers and the GaAs y Sb 1-y , layers are unintentionally doped.

9. The superlattice barrier structure of claim 8 , wherein the repeating sequence of AlAs x Sb 1-x , GaAs y Sb 1-y , and InAs 1-z Sb z define a period of the superlattice structure, and the period is such that a first layer is AlAs x Sb 1-x , a second layer is GaAs y Sb 1-y , and a third layer is InAs 1-z Sb z .

10. The superlattice barrier structure of claim 8 , wherein the repeating sequence of AlAs x Sb 1-x , GaAs y Sb 1-y , and InAs 1-z Sb z define a period of the superlattice structure, and the period is such that a first layer is InAs 1-z Sb z , a second layer is GaAs y Sb 1-y , and a third layer is AlAs x Sb 1-x .

11. The superlattice barrier structure of claim 8 , wherein the repeating sequence of AlAs x Sb 1-x , GaAs y Sb 1-y , and InAs 1-z Sb z define a period of the superlattice structure, and the period is such that a first layer is AlAs x Sb 1-x , a second layer is InAs 1-z Sb z , a third layer is AlAs x Sb 1-x , and a fourth layer is GaAs y Sb 1-y .

12. The superlattice barrier structure of claim 8 , wherein the repeating sequence of AlAs x Sb 1-x , GaAs y Sb 1-y , and InAs 1-z Sb z define a period of the superlattice structure, and the period is such that a first layer is AlAs x Sb 1-x , a second layer is InAs 1-z Sb z , a third layer through an mth layer is an number of repeating layers of AlAs x Sb 1-x and GaAs y Sb 1-y .

13. A diode barrier infrared detector device utilizing an n-type absorber comprising:

a first contact layer, wherein the first contact layer is doped n-type;

an absorber layer adjacent to the first contact layer, wherein the absorber layer is doped n-type;

a barrier layer adjacent to the absorber layer;

an n-type material layer adjacent to the barrier layer; and

a second contact layer adjacent to the n-type material layer, wherein the second contact layer is p-doped.

14. The diode barrier infrared detector device according to claim 13 , wherein the n-type material layer and the second contact layer comprise a material having a wider bandgap than a material of the absorber layer.

15. The diode barrier infrared detector device of claim 13 , further comprising a nominally undoped i region disposed between the n-type material layer and the second contact layer.

16. The diode barrier infrared detector device of claim 13 , further comprising a nominally undoped graded gap section disposed between the n-type material layer and the second contact layer.

17. A diode barrier infrared detector device comprising:

a first contact layer;

an absorber layer adjacent to the first contact layer;

a barrier layer adjacent to the absorber layer, wherein the barrier layer comprises a diode structure formed by a p-n junction formed within the barrier layer; and

a second contact layer adjacent to the barrier layer, wherein the diode structure comprises:

an n-doped barrier layer adjacent to the absorber layer, wherein:

the n-doped barrier layer is doped at a doping level such that at least a portion of a valence band edge within the barrier layer is less than a valence band edge within the absorber layer;

the n-doped barrier layer comprises a first n-doped barrier region having a first doping level, a second n-doped barrier region having a second doping level, and a third n-doped barrier region having a third doping level;

the first n-doped barrier region is adjacent to the absorber layer;

the second n-doped barrier region is disposed between the first n-doped barrier region and the third n-doped barrier region;

the third doping level is greater than the second doping level; and

the second doping level is greater than the first doping level; and

a p-doped barrier layer disposed between the third n-doped barrier region of the n-doped barrier layer and the second contact layer.

18. The diode barrier infrared detector device of claim 17 , wherein:

a thickness of the first n-doped barrier region is greater than a thickness of the third n-doped barrier region; and

the thickness of the third n-doped barrier region is greater than a thickness of the second n-doped barrier region.

19. The diode barrier infrared detector device of claim 18 , wherein:

the first doping level is about 2.5×10 15 ;

the second doping level is about 6.0×10 16 ;

the third doping level is about 2.0'10 17 ; and

a doping level of the p-doped barrier layer is about 3.0×10 17 .

20. A diode barrier infrared detector device comprising:

a first contact layer;

an absorber layer adjacent to the first contact layer;

a barrier layer adjacent to the absorber layer, wherein the barrier layer comprises:

a superlattice structure comprising a repeating sequence of an AlAs x Sb 1-x layer, a GaAs y Sb 1-y layer, and an InAs 1-z Sb z layer, wherein:

0<x<1, 0<y<1, and 0<z<1;

the InAs 1-z Sb z layers are n-doped; and

the AlAs x Sb 1-x layers and the GaAs y Sb 1-y , layers are unintentionally doped;

a p-doped barrier layer, wherein the superlattice structure and the p-doped barrier layer define a p-n junction within the barrier layer; and

a second contact layer adjacent to the barrier layer.