Intersubband detector with avalanche multiplier region
A photodetector for use at wavelengths of 2 μm and longer has an intersubband absorption region to provide absorption at wavelengths beyond 2 μm, integrated with an avalanche multiplier region to provide low-noise gain. In one particular design, the intersubband absorption region is a quantum-confined absorption region (e.g., based on quantum wells and/or quantum dots).
1. A photodetector comprising:
a substrate;
a semiconductor structure positioned on the substrate, the semiconductor substrate comprising:
an avalanche multiplier region; and
a highly doped p-type region positioned on the avalanche multiplier region; and
an n-i-n structure positioned on the semiconductor structure, the n-i-n structure comprising:
a first n-type contact region positioned on the highly doped p-type region;
a quantum-confined absorption region positioned on the n-type contact region; and
a second n-type contact region positioned on the quantum confined absorption region.
2. The photodetector of claim 1 wherein the semiconductor structure comprises:
a p-i-n structure.