Mecit G., Işık M., Hasanlı N.
MATERIALS RESEARCH EXPRESS, vol.13, no.12, pp.1, 2026 (SCI-Expanded, Scopus)
-
Publication Type:
Article / Article
-
Volume:
13
Issue:
12
-
Publication Date:
2026
-
Doi Number:
10.1088/2053-1591/ae7af9
-
Journal Name:
MATERIALS RESEARCH EXPRESS
-
Journal Indexes:
Scopus, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest), Science Citation Index Expanded (SCI-EXPANDED), Chemical Abstracts Core, Compendex, INSPEC, Directory of Open Access Journals
-
Page Numbers:
pp.1
-
TED University Affiliated:
Yes
Abstract
Abstract
Layered GaS is increasingly considered for ultraviolet optoelectronics, van der Waals nanophotonics, and nonlinear optical platforms; however, a self-consistent bulk dielectric reference connecting its dispersion, absorption, optical-conductivity, and energy-loss response remains limited. Here, we report the room-temperature effective pseudo-dielectric response of Bridgman-grown bulk GaS single crystals determined by spectroscopic ellipsometry over the photon-energy range 1.2–6.0 eV. From freshly cleaved (001) surfaces, the refractive index, extinction coefficient, absorption coefficient, optical conductivity, and surface/volume energy-loss functions are extracted within a unified framework. First-derivative analysis of the absorption coefficient identifies the indirect absorption onset at approximately 2.47 eV, consistent with previous optical benchmarks. In the transparent spectral region, the Wemple–DiDomenico single-effective-oscillator model yields
E
0
≈
6.01
eV,
E
d
≈
34.6
eV, and a static refractive index of
n
0
≈
2.60
. Pronounced optical-conductivity features near 3.9 and 5.3 eV are discussed in relation to previously established interband critical-point transitions. In addition, order-of-magnitude third-order nonlinear optical parameters are estimated using Miller’s generalized rule and are presented strictly as guides for nonlinear-experiment design. The resulting dataset provides an effective ordinary-channel bulk reference for modeling GaS-based UV photodetectors, reconfigurable phase-change photonic components, nonlinear optical elements, and high-refractive-index van der Waals nanophotonic structures.