Kuwait University

QSSPC technique monitors the material quality during fabrication process. Lifetime data is interpreted and open-circuit voltage (versus illumination) curve is mapped.
(Standard offline wafer life-time tool: WCT-120)

Available measurements:

  • Lifetime
  • Resistivity
  • Emitter saturation current density
  • Trap density


  • One-sun Voc Lifetime measurement range: 100 ns to greater than 10 ms
  • Measurement (analysis) modes: QSSPC, transient and generalized lifetime analysis
  • Resistivity measurement range: 3–600 (undoped) Ohms/sq.
  • Available light bias range: 0–50 suns
  • Typical calibrated injection range: 1013–1016 cm-3
  • Available spectrum: White-light and IR illumination
  • Sensor area: 40-mm diameter
  • Standard diameter: 40–210 mm (smaller sizes may be measured)
  • Wafer thickness range: 10–2000 μm (calibrated) (other thicknesses may be measured)


Suns-Voc stage is usually attached with WCT-120. It displays standard I-V curve format as well as the Suns-Voc curve. The measurement is at open circuit so the effect of series resistance is negligible.


  • Wafer stage controlled at 25°C
  • Fine-point voltage probe
  • Magnetic-probe compatibility
  • Xenon flash lamp with set of neutral-density filters
  • Height-adjustable back column for fine-tuning intensity range

Parameters reported for each measurement:

  • Implied I-V curve at open circuit: materials limit to efficiency
  • Pseudo-efficiency
  • Pseudo-fill-factor
  • Two-diode analysis
  • Shunt value
  • Typical calibrated illumination range:0.006–6 suns
  • Wafer size, standard configuration: Maximum 210-mm diameter

Quasi Steady State Photo Conductance