Progress on MBE grown type-II superlattice photodiodes

C. J. Hill, Jian V. Li, J. M. Mumolo, S. G. Gunapala

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The closely lattice-matched material system of InAs, GaSb, and AlSb, commonly referred to as the 6.1Å material system, has emerged as a fertile ground for the development of new solid-state devices. The flexibility of the system in simultaneously permitting type-I, type-II staggered, and type-II broken-gap band alignments has been the basis for many novel, high-performance heterostructure devices in recent years, including the GalnSb/InAs type-II strained layer superlattice infrared detectors proposed by Smith and Mailhiot [1] in 1987. The type-II superlattice design promises optical properties comparable to HgCdTe, better uniformity, reduced tunneling currents, suppressed Auger recombination, and normal incidence operation [ 2,3]. In 1990, Chow and co-workers first reported Ga 1-xInxSb/InAs superlattice materials with high structural quality, LWIR photoresponse, and LWIR photoluminescence [4]. Later, researchers demonstrated excellent detectivity (approaching HgCdTe, 8-μm cutoff, 77K) on individual superlattice devices [5]. Currently, superlattice detector technology is undergoing the transition from single element detectors into high-performance focal plane imaging arrays [6]. Here we report on the status of superlattice diodes grown and fabricated at the Jet Propulsion Laboratory designed for infrared absorption in the mid (2-5 μm) and long wavelength (8-12 μm) infrared ranges. Our mid-wavelength infrared devices display a zero bias differential resistance-area product as high as 1e6 Ohmcm2 at 80K with a 5μm cutoff, with a corresponding detectivity of nearly 1e13 Jones. These detectors continue to function at room temperature with a detectivity of nearly 1e9 Jones. In the long wavelength region, we have produced devices with detectivities as high as 8×1010 Jones with a differential resistance-area product greater than 6 Ohmcm2 at 80K with a long wavelength cutoff of approximately 12μm. A typical IV curve a 12μm cutoff device is shown in Figure 1. Responsivity, detectivity and quantum efficiency for a typical 12μm cutoff device is shown in Figure 2. In addition to detector performance results, recent progress in epitaxial regrowth as a passivation method and progress on long-wavelength imaging array fabrication will be presented.

Original languageEnglish
Title of host publication2006 Digest of the LEOS Summer Topical Meetings
Number of pages2
Publication statusPublished - 2006 Dec 1
Event2006 LEOS Summer Topical Meetings - Quebec City, QC, Canada
Duration: 2006 Jul 172006 Jul 19

Publication series

NameLEOS Summer Topical Meeting
ISSN (Print)1099-4742


Other2006 LEOS Summer Topical Meetings
CityQuebec City, QC

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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