Direct Observation of Grain Boundary PN Junction Potentials in CIGS Using Photoemission and Low Energy Electron Microscopy (PELEEM)

  • Calvin K. Chan
  • , Taisuke Ohta
  • , Gary L. Kellogg
  • , Lorelle Mansfield
  • , Kannan Ramanathan
  • , Rommel Noufi

Research output: Contribution to conferencePaperpeer-review

Abstract

Spectroscopic microscopies with chemical and electronic structure information have become important tools for understanding the complex structure-property-performance relationships of high performing Cu(In1-xGax)Se2 (CIGS) photovoltaic materials and devices. Here, we describe the application of spectrally resolved photoemission and low-energy electron microscopy (spec-PELEEM) to CIGS. With the ability to map relative electric potentials with high fidelity, a large variation in the built-in pn junction potential was observed at CIGS grain boundaries. In any given 20 μm region, the built-in voltage spanned the range from depletion (∼ 0.5 V) to inversion (∼ 1.4 V). These grain-to-grain variations could explain the electron collection efficiency of CIGS grain boundaries and devices. These results highlight the potential of spec-PELEEM to solve critical structure-property-performance issues facing compound thin-film materials.

Original languageAmerican English
Pages1908-1911
Number of pages4
DOIs
StatePublished - 15 Oct 2014
Event40th IEEE Photovoltaic Specialist Conference, PVSC 2014 - Denver, United States
Duration: 8 Jun 201413 Jun 2014

Conference

Conference40th IEEE Photovoltaic Specialist Conference, PVSC 2014
Country/TerritoryUnited States
CityDenver
Period8/06/1413/06/14

Bibliographical note

Publisher Copyright:
© 2014 IEEE.

NLR Publication Number

  • NREL/CP-5K00-63536

Keywords

  • electron microscopy
  • II-VI semiconductor materials
  • p-n junctions
  • photoelectron microscopy
  • photovoltaic cells
  • spectroscopy
  • thin-film devices

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