Photocurrent Measurement
Laboratory

The laboratory provides facilities for studying the optoelectronic properties of semiconductors, thin films, heterostructures, low dimensional materials, and organic or hybrid systems. The setup enables precise measurements of photogenerated signals over a wide spectral and temperature range.

Steady state photocurrent spectroscopy measures the photocurrent as a function of photon energy, offering insight into semiconductor electronic structure, charge transport, and recombination. Illumination generates electron–hole pairs collected under an applied electric field, and the resulting change in conductivity depends on carrier generation quantum yield and carrier mobility.

The photocurrent spectrum is obtained by scanning wavelength, and responsivity (R) is used to quantify photocurrent normalized by light intensity. Light modulation and lock in detection allow measurement of very weak signals, with full control via LabView software.

Capabilities:

• Spectral photocurrent measurements (IPCE/EQE)
• AC photocurrent detection with monochromatic, modulated light
• I–V characteristics under dark and illuminated conditions
• Temperature dependent photoconductivity
• Detection of picoampere level currents

Equipment:

• Xenon, halogen, supercontinuum sources; optional CW lasers
• Monochromator and mechanical chopper
• Voltage source and optional preamplifier
• Lock in amplifier
• Optional vacuum chamber for low temperature or air sensitive samples

These techniques provide information on:

• exciton to charge conversion,
• carrier mobility and lifetime,
• photocarrier generation efficiency and recombination,
• defects and trap states.

Such data are essential for photovoltaics, photodetectors, organic/hybrid optoelectronics, and quantum material research.