UV-Excited Photoluminescence Measurement System

Model: MUVPL-375
UV-Excited Photoluminescence Measurement System MUVPL-375

This system irradiates a sample with 375 nm laser light and performs spectroscopic measurement of the resulting photoluminescence.

■Features
  • Excitation wavelength: 375 nm, 20 mW
  • Compact fiber-optic spectrometer
  • Variable incidence angle: 45°
  • Camera for observing the measurement position

■Specifications
Laser wavelength 375 nm
Measurement wavelength range 200 nm to 800 nm
Wavelength resolution 1 nm (FWHM)
Detector 2048-element CCD array

*Specifications and appearance are subject to change without notice for improvement.
 

Model: MUVPL-193
UV-Excited Photoluminescence Measurement System MUVPL-193

This system irradiates a sample with 193 nm laser light and performs spectroscopic measurement of the resulting photoluminescence.

■Features
  • Excitation wavelength: 193 nm
  • High-sensitivity back-illuminated CCD
  • Reflective optics for ultraviolet
  • Variable incidence angle: 0°, 45°
  • Variable detection angle: 20° to 70°
  • XYZ scanning of the sample
  • Camera for observing the measurement position

■Specifications
Laser wavelength 193 nm
Measurement wavelength range 200 nm to 400 nm
Wavelength resolution 3 nm (FWHM)
Detector Back-illuminated CCD

*Specifications and appearance are subject to change without notice for improvement.
 

Model: MUVPL-213/325
UV-Excited Photoluminescence Measurement System MUVPL-213/325

This system irradiates a sample with 213 nm or 325 nm laser light and performs spectroscopic measurement of the resulting photoluminescence.

■Features
  • Excitation wavelengths: 213 nm, 325 nm
  • High-resolution monochromator
  • Reflective optics for ultraviolet
  • Mapping measurement (optional)

■Specifications
Laser wavelength 213 nm, 325 nm
Spectroscopic optics Monochromator + photomultiplier tube
Signal measurement system Lock-in amplifier + chopper

*Specifications and appearance are subject to change without notice for improvement.

■Basic Principle of Photoluminescence (PL)

Photoluminescence (PL) is an optical technique in which a material is irradiated with high-energy light (excitation light), exciting electrons in the valence band to higher energy levels such as the conduction band, and the light (photons) emitted as they return to the ground level is detected and analyzed. This phenomenon is widely used to evaluate electronic states and diagnose material quality, mainly in semiconductor materials and phosphors.

As shown in the figure, electrons at the ground level (in most cases, the top of the valence band) absorb the energy of the externally applied excitation light and are excited to a higher energy level (typically the conduction band). This creates electron-hole pairs.

Diagram of the basic principle

However, excited electrons do not necessarily recombine immediately and undergo radiative transitions. In many cases, they pass through relaxation mechanisms such as those shown below before recombining.

  • Non-radiative relaxation: A process in which excited electrons lose energy as heat through interaction with lattice vibrations (phonons). No photons are emitted in this process.
  • Trapping by defect or impurity levels: Electrons may be temporarily captured at intermediate levels formed by defects or impurities in the crystal lattice, and when they return from there to the ground level, light with energy lower than the band gap may be emitted.

Because of these processes, the emission spectrum observed in PL measurements does not necessarily directly reflect the energy difference between the incident photons and the band gap, but is influenced by the various relaxation pathways within the material.

PL is a highly sensitive evaluation technique that can be applied to samples without contact or damage. In addition to analyzing band structures and energy levels, it can comprehensively provide information on crystallinity, defect density, impurity distribution, and more. It is regarded as an especially important technique for materials development and quality control of semiconductor devices, and for the evaluation of quantum dots and low-dimensional structures.