X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells

J Vis Exp. 2019 Aug 20:(150). doi: 10.3791/60001.

Abstract

X-ray beam induced current (XBIC) measurements allow mapping of the nanoscale performance of electronic devices such as solar cells. Ideally, XBIC is employed simultaneously with other techniques within a multi-modal X-ray microscopy approach. An example is given herein combining XBIC with X-ray fluorescence to enable point-by-point correlations of the electrical performance with chemical composition. For the highest signal-to-noise ratio in XBIC measurements, lock-in amplification plays a crucial role. By this approach, the X-ray beam is modulated by an optical chopper upstream of the sample. The modulated X-ray beam induced electrical signal is amplified and demodulated to the chopper frequency using a lock-in amplifier. By optimizing low-pass filter settings, modulation frequency, and amplification amplitudes, noise can efficiently be suppressed for the extraction of a clear XBIC signal. A similar setup can be used to measure the X-ray beam induced voltage (XBIV). Beyond standard XBIC/XBIV measurements, XBIC can be measured with bias light or bias voltage applied such that outdoor working conditions of solar cells can be reproduced during in-situ and operando measurements. Ultimately, the multi-modal and multi-dimensional evaluation of electronic devices at the nanoscale enables new insights into the complex dependencies between composition, structure, and performance, which is an important step towards solving the materials' paradigm.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Video-Audio Media

MeSH terms

  • Amplifiers, Electronic*
  • Electric Power Supplies*
  • Microscopy / instrumentation
  • Microscopy / methods*
  • Signal-To-Noise Ratio*
  • Solar Energy*
  • X-Rays