Tunneling barrier infrared detector devices
Embodiments of the present disclosure are directed to infrared detector devices incorporating a tunneling structure. In one embodiment, an infrared detector device includes a first contact layer, an absorber layer adjacent to the first contact layer, and a tunneling structure including a barrier layer adjacent to the absorber layer and a second contact layer adjacent to the barrier layer. The barrier layer has a tailored valence band offset such that a valence band offset of the barrier layer at the interface between the absorber layer and the barrier layer is substantially aligned with the valence band offset of the absorber layer, and the valence band offset of the barrier layer at the interface between the barrier layer and the second contact layer is above a conduction band offset of the second contact layer.
1. An infrared detector device comprising:
a first contact layer;
an absorber layer adjacent to the first contact layer, wherein the absorber layer is doped p-type;
a first barrier layer adjacent to the absorber layer;
an n-type layer adjacent to the first barrier layer, wherein:
a bandgap of the n-type layer is greater than a bandgap of the absorber layer; and
a valence band offset of the first barrier layer at an interface between the first barrier layer and the n-type layer is above a conduction band offset that is within the n-type layer;
a second barrier layer adjacent to the n-type layer; and
a second contact layer adjacent to the second barrier layer.
2. The infrared detector device of claim 1 , wherein the second barrier layer comprises nominally undoped (GaSb) y (AlAs 0.08 Sb 0.92 ) 1-y .
3. The infrared detector device of claim 1 , wherein the first barrier layer comprises a graded structure.
4. The infrared detector device of claim 1 , wherein:
the first barrier layer comprises (GaSb) x (AlAs 0.08 Sb 0.92 ) 1-x with linearly graded x values; and
the first barrier layer is doped p-type.
5. The infrared detector device of claim 1 , further comprising a third barrier layer positioned between the second barrier layer and the second contact layer such that the third barrier layer is adjacent to the second contact layer, wherein a valence band offset of the third barrier layer at an interface between the third barrier layer and the second contact layer is above a conduction band offset of the second contact layer.
6. The infrared detector device of claim 5 , wherein the third barrier layer comprises (GaSb) x (AlAs 0.08 Sb 0.92 ) 1-x with x value chosen such that there is the broken gap type II band alignment with the second contact layer.
7. The infrared detector device of claim 5 , wherein the third barrier layer comprises (GaSb) x (AlAs 0.08 Sb 0.92 ) 1-x .
8. The infrared detector device of claim 1 , wherein the n-type layer and the second contact layer comprise a mid-wave infrared material having a bandgap wider than the absorber layer.