Direct-Gap 2.1-2.2 eV AlInP Solar Cells on GaInAs/GaAs Metamorphic Buffers

Michelle Vaisman, Kunal Mukherjee, Taizo Masuda, Kevin Nay Yaung, Eugene A. Fitzgerald, Minjoo Larry Lee

Research output: Contribution to journalArticlepeer-review


AlInP offers the highest direct bandgap (Eg) among nonnitride III-V materials, making it attractive for top cell applications in five-to-six-junction solar cells. We present novel 2.05-2.15 eV direct-gap AlInP solar cells, grown on GaInAs/GaAs-graded buffers by metal-organic chemical vapor deposition (MOCVD). Despite the high Al content of 36-39% in the active regions, secondary ion mass spectrometry results indicate oxygen concentrations less than 3.5 × 1016 cm-3. The AlInP devices we present here exhibit superior photovoltaic performance to GaP and similar performance to metamorphic GaInP solar cells, reaching a Eg-voltage offset of 0.57 V. Design enhancements based on device and material characterization led to improvements of over ∼ 4 × in short-circuit current density from our first-generation AlInP devices. Our results indicate that a p-i-n device design is necessary to account for low minority carrier diffusion lengths in AlInP solar cells; additionally, diffusion of Zn dopant atoms poses another challenge that must be accounted for in cell design. The effect of offcut on cell performance was also investigated, with improved solar cells on samples offcut toward the A plane. The promising results in this work provide an alternative path toward realizing high-Eg top cells with possible applications in upright metamorphic multijunction solar cells.

Original languageEnglish (US)
Article number7359094
Pages (from-to)571-577
Number of pages7
JournalIEEE Journal of Photovoltaics
Issue number2
StatePublished - Mar 2016
Externally publishedYes


  • AlInP
  • III-V semiconductor materials
  • Wide bandgap
  • photovoltaic cell

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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