II-VI Semiconductor Materials | ZnSe, ZnS, ZnTe, CdSe & CdS

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Popular Use Cases

ZnSe — CO₂ (10.6 µm) optics, thermal imaging windows
ZnS — Multi-spectral VIS–IR optics, rugged windows
ZnTe — Nonlinear / THz generation, EO devices
CdSe — Photodetectors, PV, quantum dot research
CdS — Window/buffer layers, acousto-optics

Spec Tips for Quotes

Diameter (or window size) and thickness
Polish (SSP/DSP) and roughness target
Coating type and wavelength band (e.g., 3–5 µm, 8–12 µm)
Edge specs (bevel, chamfer) and quantity
Any bow/warp/flatness tolerances

Handling & Safety

Handle with gloves; avoid abrasion on polished faces
Store dry in protective cases; clean with approved solvents only
Follow EHS procedures for cadmium-containing materials (CdS, CdSe)

II–VI Semiconductor Materials for Optics, Photonics and Electronic Devices

II–VI semiconductor materials are compound semiconductors formed from elements in Groups II and VI of the periodic table. Materials such as zinc selenide (ZnSe), zinc sulfide (ZnS), zinc telluride (ZnTe), cadmium selenide (CdSe), and cadmium sulfide (CdS) are valued for their wide or direct bandgaps, optical transparency, photoconductive behavior, and tunable electronic properties.

These characteristics make II–VI materials important for infrared optics, photodetectors, laser systems, thermal imaging, terahertz devices, photovoltaics, quantum dot research, and advanced optoelectronic device fabrication. UniversityWafer supplies II–VI wafers, optical windows, substrates, and diced pieces for university laboratories, industrial research, and semiconductor development.

II–VI Materials Available for Research

Zinc Selenide (ZnSe)

Zinc selenide is a widely used infrared optical material with good transmission across visible and infrared wavelengths. ZnSe is commonly selected for CO₂ laser optics operating near 10.6 µm, thermal imaging windows, infrared lenses, beam splitters, and spectroscopic components.

Its relatively low absorption and broad optical transmission make ZnSe suitable for high-power laser systems, infrared instrumentation, and research involving mid-wave and long-wave infrared radiation.

Zinc Sulfide (ZnS)

Zinc sulfide offers broad visible-to-infrared transmission and is frequently used for rugged optical windows, multispectral imaging systems, and protective infrared components. Multispectral ZnS can transmit both visible and infrared wavelengths, making it useful in systems that combine visual imaging with thermal detection.

ZnS substrates may also be used in phosphors, electroluminescent devices, optical coatings, and semiconductor thin-film research.

Zinc Telluride (ZnTe)

Zinc telluride is a direct-bandgap semiconductor used in terahertz generation and detection, nonlinear optics, electro-optic sampling, infrared devices, and photovoltaic research. ZnTe crystals are especially valuable for experiments that require efficient interaction between optical and terahertz radiation.

Researchers also investigate ZnTe for light-emitting devices, radiation detectors, thin-film solar cells, and compound semiconductor heterostructures.

Cadmium Selenide (CdSe)

Cadmium selenide is a direct-bandgap semiconductor with strong light absorption and emission properties. It is commonly studied for photodetectors, photovoltaic cells, visible-light sensors, thin-film transistors, nanocrystals, and quantum dots.

CdSe quantum dots are widely investigated because their optical properties can be adjusted by changing particle size, allowing researchers to control emission wavelength for imaging, sensing, display, and optoelectronic applications.

Cadmium Sulfide (CdS)

Cadmium sulfide is used in photoconductive detectors, thin-film photovoltaics, acousto-optic devices, optical filters, and semiconductor heterojunctions. In solar-cell research, CdS is commonly studied as a transparent window or buffer layer because it allows light to enter the absorber while supporting charge separation.

CdS is also investigated for visible-light photodetectors, gas sensors, photocatalysis, and nanoscale semiconductor devices.

Comparison of Common II–VI Semiconductor Materials

Material	Key Property	Common Research Applications
ZnSe	Broad infrared transmission	CO₂ laser optics, thermal imaging, IR windows and lenses
ZnS	Visible-to-infrared transmission	Multispectral windows, protective optics, phosphors and coatings
ZnTe	Nonlinear and electro-optic response	THz generation, electro-optic sampling, photovoltaics and detectors
CdSe	Direct bandgap and tunable optical emission	Photodetectors, quantum dots, solar cells and optoelectronics
CdS	Photoconductive and transparent-buffer behavior	Thin-film photovoltaics, sensors, detectors and acousto-optics

Optical and Electronic Properties

The performance of II–VI semiconductor materials depends on composition, crystal quality, doping, thickness, surface preparation, and operating wavelength. Important properties include:

Optical transmission: Depending on the material and grade, II–VI substrates may transmit visible, near-infrared, mid-wave infrared, or long-wave infrared radiation.
Direct bandgaps: Many II–VI compounds efficiently absorb and emit light, making them useful for photodetectors, LEDs, lasers, and photovoltaic devices.
High refractive index: These materials support compact optical components, lenses, windows, and coated infrared elements.
Photoconductivity: CdS and CdSe can change electrical conductivity when illuminated, supporting light-sensing applications.
Nonlinear optical response: ZnTe is widely studied for frequency conversion, electro-optic sampling, and terahertz generation.
Tunable optical behavior: Nanostructured CdSe and related materials can be engineered for specific absorption and emission wavelengths.

Available Forms and Custom Specifications

UniversityWafer can supply II–VI materials in several forms to support optical, semiconductor, and thin-film research:

Single-crystal wafers
Optical windows
Polished substrates
Diced chips and small research pieces
Single-side polished or double-side polished surfaces
Optical, research, or device-grade materials
Custom thicknesses and lateral dimensions
Flats, notches, beveled edges, or chamfered edges
Anti-reflective, high-reflective, or protective coatings

Specifications may include diameter, thickness, crystal orientation, surface roughness, bow, warp, flatness, coating band, transmission range, and packaging requirements. Availability varies by material and requested grade.

Infrared Optics and Laser Applications

II–VI materials are widely used in infrared systems because several compounds provide useful transmission across the mid-infrared and long-wave infrared spectrum. ZnSe is particularly important for high-power CO₂ laser systems, thermal cameras, spectroscopy, beam delivery, and infrared imaging.

Typical optical components include:

Infrared windows and viewports
Laser lenses and focusing elements
Beam splitters and beam combiners
Protective optical windows
Thermal imaging components
Infrared filters
Optical resonator components

Surface finish and coating selection are important because reflection losses can be significant for high-index materials. Anti-reflective coatings may be specified for visible, near-infrared, mid-wave infrared, or long-wave infrared bands.

Photodetectors and Optoelectronic Devices

CdS, CdSe, ZnTe, and related II–VI materials are widely investigated for photodetection because their electrical and optical response can be tailored to specific wavelengths. Researchers use these substrates and thin-film materials to develop:

Visible-light photodetectors
Infrared sensors
Photoconductive cells
Thin-film transistors
Optical switches
Radiation detectors
Light-emitting devices
Integrated optoelectronic structures

The choice of material depends on the target wavelength, bandgap, detector architecture, surface quality, electrode design, and compatibility with deposited semiconductor layers.

Terahertz and Nonlinear Optical Research

ZnTe is commonly used in terahertz time-domain spectroscopy because it can generate and detect terahertz pulses through nonlinear optical and electro-optic interactions. It is also used in frequency conversion, optical modulation, ultrafast laser experiments, and electro-optic sampling.

For these applications, researchers may require specific crystal orientations, thicknesses, surface polish, and optical coatings to maximize signal strength and minimize reflection losses.

Photovoltaic and Thin-Film Research

CdS and CdSe are frequently studied in thin-film solar cells and semiconductor heterojunctions. CdS commonly serves as a window or buffer layer, while CdSe may be used as an absorber, sensitizer, quantum-dot material, or component in hybrid photovoltaic structures.

Researchers may deposit these materials using chemical bath deposition, thermal evaporation, sputtering, molecular beam epitaxy, chemical vapor deposition, or solution-based processing. Substrate cleanliness, roughness, and surface chemistry can strongly influence film adhesion, grain growth, charge transport, and device efficiency.

Surface Preparation and Optical Coatings

Proper surface preparation is essential for both optical and semiconductor applications. Available options may include:

Optical polish: Reduces surface scatter and improves transmission.
Single-side polish: Suitable for many thin-film deposition and device experiments.
Double-side polish: Useful for transmission measurements and optical systems.
Epi-ready surfaces: Prepared for semiconductor film growth or interface-sensitive experiments.
Anti-reflective coatings: Reduce Fresnel reflection over a selected wavelength range.
High-reflective coatings: Support mirrors, laser cavities, and beam-control systems.
Protective coatings: Improve durability in demanding optical environments.

Handling and Safety Considerations

II–VI optical surfaces should be handled with clean, powder-free gloves and stored in protective containers to prevent scratches, contamination, and moisture exposure. Polished faces should not be placed directly against hard surfaces.

Cadmium-containing materials such as CdS and CdSe require appropriate laboratory controls. Researchers should follow their institution's environmental health and safety procedures for handling, machining, cleaning, storage, and waste disposal. Cutting, grinding, or polishing cadmium compounds may require additional engineering controls because these processes can produce hazardous dust.

Information to Include in Your Quote Request

To help us identify the most appropriate II–VI material for your research, include the following information:

Material: ZnSe, ZnS, ZnTe, CdSe, or CdS
Required form: wafer, window, substrate, or diced piece
Diameter, length, width, and thickness
Single-side or double-side polish
Surface roughness requirement
Crystal orientation, when applicable
Optical transmission wavelength or operating band
Anti-reflective, reflective, or protective coating requirements
Bow, warp, flatness, or edge requirements
Quantity and packaging preferences

Request II–VI Semiconductor Materials

UniversityWafer supplies II–VI semiconductor wafers, optical substrates, windows, and diced pieces for infrared optics, photonics, photodetectors, photovoltaics, terahertz systems, and compound semiconductor research. Send us your required material, dimensions, surface finish, wavelength range, coating specifications, and quantity for a fast quote.

II–VI Semiconductor Materials (ZnSe, ZnS, ZnTe, CdSe, CdS)