Broadband photoresponse from InAs quantum dots embedded in a graded well for visible to mid-infrared detection

Abstract

Interband and intersubband transitions in self-assembled InAs quantum dots embedded in an InGaAs graded well have been investigated for their use in visible to mid-infrared (0.4 -20 µm) detection applications. The materials were grown by molecular beam epitaxy and characterized using atomic force microscopy and photoluminescence. Devices were fabricated from the multiple quantum dot structures in order to measure the normal incident photoresponse at 77 and 300 K. In addition, the dark current was measured in the temperature range of 77 -300 K for the devices. A dual broadband photoresponse from the interband and intersubband transitions was measured to be 0.5 to 1.0 µm and 2.0 to 14.0 µm, respectively.