All InGaAs Unipolar Barrier Infrared Detectors

Unipolar barrier detector design is a challenge for InGaAs material system since there is a lack of proper barrier material that blocks majority carriers and allows unimpeded flow of minority carriers. As a bandgap engineering solution, Al/Sb free all InGaAs unipolar barrier detectors have been numerically designed here by compositionally graded and delta-doped layers. Comparison with conventional heterojunction detectors results that there is at least one order of magnitude improvement in dark current without compromising any photoresponse performance. Detailed simulation characterization studies including sensitivity analysis with respect to the design parameters verify the robustness of the proposed structure.