Optical research in our laboratory focuses on semiconducting layered materials, which include:
■ transition metal dichalcogenides (MoS2, MoSe2, MoTe2, WS2, WSe2, ReSe2),
■ metal monochalcogenides(GaS, GaSe, GeS, InSe),
■ chromium trihalides (CrBr3, CrCl3, CrI3),
using a variety of optical microscopy techniques (diameter of the spot of excitation light on the order of single microns), such as:
■ Raman scattering (RS),
■ photoluminescence (PL),
■ photoluminescence excitation (PLE),
■ reflectance contrast (RC),
■ in the temperature range (4.2 K - 350 K),
■ in magnetic fields up to 17 T.
The main element of the setup is the Princeton Instruments SpectraPro HRS 750 mm
spectrometer equipped with a set of three diffraction gratings (300, 600 and 1800) with
CCD PyLoN eXcelon camera (spectral range 400 nm - 1100 nm) cooled with liquid nitrogen.
It has two inputs used for signal detection from:
■ continuous Cryovac Konti Micro cryostat enabling measurements in the temperature range (4.2 K - 350 K), placed on a motorized stage enabling spatial mapping.
■ superconductiong Cryogenic magnet enabling measurements in a magnetic field up to 17 T. and in the temperature range (5 K - 300 K). The sample is placed in a specially designed probe on a piezo stage elements enabling spatial mapping.
A set of lasers with wavelengths: 405 nm, 488 nm, 515 nm, 561 nm, 633 nm, 660 nm and 785 nm, and a halogen lamp are used for excitation. In addition, tuned lasers with the following ranges can be used to measure PL spectra with other wavelengths or in the case of PLE spectra measurements: 575 - 625 nm, 620 - 670 nm, 700 - 860 nm.
The automated system relies on the HORIBA LabRAM HR spectrometer with CCD (spectral range
200 nm - 1000 nm) and InGaAs cameras (spectral range 800 nm - 1600 nm), which is coupled to the motorized stage enabling
is used for Raman scattering and photoluminescence measurements at room temperature and a wide spectral range from near ultraviolet to near infrared.