Carrier dynamics in MOVPE-grown bulk dilute nitride materials for multi-junction solar cells

Yongkun Sin, Stephen Lalumondiere, Toby Garrod, Tae Wan Kim, Jeremy Kirch, Luke Mawst, William T. Lotshaw, Steven C. Moss

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

10 Scopus citations


Dilute nitride materials with a 1eV band-gap lattice matched to GaAs substrates are attractive for high-efficiency multi-junction solar cells. Carrier lifetime measurements are crucial in optimizing material growth and p-i-n field-aided carrier-extraction-device design. One research group has reported carrier lifetimes of MBE-grown bulk InGaNAsSb materials, but there has been no report of carrier lifetime measurements from bulk InGaNAsSb grown by MOVPE. In this study, we report the growth of bulk InGaNAsSb by MOVPE and the first carrier lifetime measurement from MOVPE-grown bulk InGaNAsSb materials with Eg= 1.0 - 1.2eV at 300K. We studied carrier dynamics in MOVPE-grown bulk dilute nitride materials nominally lattice matched to GaAs (100) substrates: 1μm thick In0.035GaN0.025As (E g= 1.0eV at 300K) and ∼0.2μm thick In (0.05-0.07)GaN(0.01-0.02)AsSb(0.02-0.06) layers (Eg= 1.2eV at 300K). Both structures are fully strained. The incorporation of N in InGaNAs leads to degradation in photoluminescence efficiency, but prior studies indicate the addition of Sb in MBE-grown InGaNAsSb improved the PL efficiency. Two-step post-growth thermal annealing processes were optimized to obtain maximum PL efficiencies that yielded a typical blue shift of 50 and 30meV for InGaNAs and InGaNAsSb, respectively. We employed a streak camera to measure carrier lifetimes from both as-grown and thermally annealed samples. Carrier lifetimes of <30psec were obtained from the InGaNAs samples, whereas carrier lifetimes of up to ∼150psec were obtained from the InGaNAsSb samples. We discuss possible reasons for short carrier lifetimes measured from MOVPE-grown InGaNAs(Sb) materials.

Original languageEnglish
Title of host publicationPhysics and Simulation of Optoelectronic Devices XIX
StatePublished - 2011
EventPhysics and Simulation of Optoelectronic Devices XIX - San Francisco, CA, United States
Duration: 24 Jan 201127 Jan 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferencePhysics and Simulation of Optoelectronic Devices XIX
Country/TerritoryUnited States
CitySan Francisco, CA


  • Dilute nitrides
  • InGaNAsSb
  • TR-PL
  • carrier lifetime
  • multi-junction solar cells


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