Gallium Selenide (GaSe) Single Crystal Substrate – High-Purity Imported Material

Overview

Gallium Selenide (GaSe) is a layered II–VI semiconductor crystal with exceptional optoelectronic properties, widely employed in nonlinear optical (NLO) frequency conversion, terahertz (THz) generation and detection, and as a substrate for epitaxial growth of 2D materials. This high-purity GaSe single crystal substrate is sourced from a U.S.-based manufacturer and distributed under strict quality control by Hefei Kejing Materials Technology Co., Ltd. Engineered for precision photonics research and device prototyping, the material exhibits an indirect bandgap of 2.1 eV and a direct transition at ~2.6 eV, enabling broad spectral response from visible to mid-infrared wavelengths. Its hexagonal crystal structure (space group P6₃mc) supports strong anisotropy and cleavage along the basal (0001) plane—facilitating atomically flat surface preparation without polishing.

Key Features

• High-purity single-crystal GaSe grown by vertical Bridgman method, verified by XRD and EDX analysis
• Cleaved along the orientation, delivering atomically smooth surfaces with RMS roughness < 0.3 nm (as measured by AFM)
• Density: 5.03 g/cm³; Melting point: 960 °C (1233 K); Thermal expansion coefficient: ~28 × 10⁻⁶ K⁻¹ (c-axis)
• Electron mobility up to 6000 cm²·V⁻¹·s⁻¹ at 300 K—among the highest reported for layered semiconductors
• Vacuum-sealed in Class 100 cleanroom bags within Class 1000 cleanroom environment, ensuring particulate contamination < 10 particles/m³ (≥0.5 µm)
• Trace impurity content ≤ 1 × 10¹⁷ cm⁻³ (measured via SIMS), minimizing non-radiative recombination pathways

Sample Compatibility & Compliance

This GaSe substrate is compatible with standard thin-film deposition techniques including molecular beam epitaxy (MBE), pulsed laser deposition (PLD), and sputtering. Its thermal stability supports in-situ annealing up to 400 °C under UHV conditions. All wafers undergo full spectroscopic characterization—including Raman mapping (E₂g mode at ~220 cm⁻¹), UV-Vis-NIR transmission, and photoluminescence excitation (PLE)—prior to shipment. The material complies with ASTM F1529-22 for semiconductor substrate dimensional tolerances and meets ISO 14644-1 Class 5 (Class 100) packaging requirements. Documentation includes Certificate of Analysis (CoA), traceable metrology reports, and batch-specific crystallinity verification.

Software & Data Management

While GaSe itself is a passive substrate material, its integration into optoelectronic systems often requires alignment with industry-standard data acquisition and calibration workflows. Users routinely interface GaSe-based THz emitters/detectors with LabVIEW™-controlled lock-in amplifiers (e.g., Zurich Instruments HF2LI) or Python-based pulse characterization platforms (e.g., using PyTorch for time-domain waveform analysis). All supplied substrates are accompanied by a digital metadata package—including crystallographic orientation maps, surface topography scans (BAM/AFM), and optical constants derived from ellipsometry (n, k vs. λ from 300–12000 nm). Data files conform to HDF5 format with embedded MIAME-compliant metadata tags, supporting FAIR (Findable, Accessible, Interoperable, Reusable) principles for academic and industrial R&D traceability.

Applications

• Optical parametric oscillators (OPOs) and difference-frequency generation (DFG) in the 3–12 µm mid-IR range
• Terahertz time-domain spectroscopy (THz-TDS) emitters and electro-optic sampling detectors
• Van der Waals heterostructure assembly—particularly with TMDCs (MoS₂, WSe₂) and graphene
• Photoconductive antenna substrates requiring low trap density and high carrier lifetime
• Reference material for calibrating ultrafast pump-probe setups operating at 800 nm and 1550 nm excitation
• Fundamental studies of exciton dynamics, valley polarization, and interlayer coupling in 2D quantum wells

FAQ

Is this GaSe substrate suitable for exfoliation into monolayers?
Yes—its weak interlayer van der Waals bonding and well-defined cleavage plane enable mechanical exfoliation down to few-layer and monolayer thicknesses using standard PDMS stamping protocols.
What is the typical surface finish after cleaving?
As-cleaved surfaces exhibit step-terrace morphology with atomic-level flatness over >10 µm domains; no post-cleavage polishing is recommended due to risk of selenium desorption.
Can I request custom orientations or doping profiles?
Custom cuts (e.g., off-axis or ) and Fe/Cr-doped variants are available upon technical review and minimum order quantity (MOQ = 5 units). Lead time: 8–12 weeks.
How is crystal quality verified prior to dispatch?
Each wafer undergoes rocking curve XRD (FWHM ≤ 0.05°), micro-PL mapping (homogeneity >95% across 5 × 5 mm²), and cross-sectional TEM for stacking fault density quantification.
Does the vacuum packaging include moisture barrier layers?
Yes—triple-laminate Al/PE/PE bags with integrated CaO desiccant and humidity indicator card (<10% RH internal environment maintained for ≥12 months).