Group II/VI Compound Semiconductor Materials
The group II-VI compound semiconductor materials are important candidates for a variety of applications ranging from light emitting diodes (LEDs) and lasers to photovoltaics. These materials consist of two elements from the second and sixth groups of the periodic table, respectively, and show a variety of diverse electronic and optical properties depending on the composition and the crystal structure. Examples include CdS (cadmium sulfide), ZnS (zinc sulfide), ZnSe (zinc selenide), CdSe (cadmium selenide), and ZnSxSe1-x (zinc sulfide-selenide).
Cadmium sulfide (CdS) is a direct band-gap semiconductor with a band gap of 2.3 to 2.5 eV that is widely used in LED and laser-diode devices. Its wide bandgap makes it an ideal material for high-efficiency LEDs and lasers. Its optical properties can also be tuned by varying the band gap and doping level, giving CdS a wide range of applications, including in optical and optoelectronic sensors.
Zinc sulfide (ZnS) is a direct band gap semiconductor with a bandgap of 3.7 to 4.3 eV. It is used as a phosphor material in display screens, but can also be used in LED and laser-diode devices. Its optical properties can be tuned by varying the band gap and doping level to produce a wide array of colors for applications such as display screens and color sensors.
Zinc selenide (ZnSe) is an indirect band gap semiconductor with a bandgap of 2.4 to 2.7 eV. It is typically used in imaging and illumination applications, such as camera lenses and microscopes, due to its excellent optical qualities. It is also used in laser-diode devices due to its broad absorption spectrum, which allows for a wide range of operating wavelengths.
Cadmium selenide (CdSe) is an indirect band gap semiconductor with a bandgap of 1.9 to 2.2 eV. It is used in LEDs and laser-diode devices due to its relatively low bandgap and high absorption coefficient. Its optical properties can be tuned by changing the doping level and bandgap, resulting in a wide range of applications.
Zinc sulfide-selenide (ZnSxSe1-x) is a family of ternary compounds consisting of zinc sulfide and selenide. This material is optically active, allowing for a wide range of colors to be created for applications such as displays screens and color sensors. Due to its ease of manufacturing, ZnSxSe1-x is also attractive for use in LEDs and laser-diode devices.
In summary, the group II-VI compound semiconductor materials are important materials for a wide range of applications in the electronics and optoelectronics industries. They consist of two elements from the second and sixth groups of the periodic table, respectively, and show a variety of diverse electronic and optical properties depending on the composition and the crystal structure. Examples include CdS (cadmium sulfide), ZnS (zinc sulfide), ZnSe (zinc selenide), CdSe (cadmium selenide), and ZnSxSe1-x (zinc sulfide-selenide). Each of these materials has a different band gap, and its optical properties can be tuned by varying the band gap and doping level. This makes them attractive for a variety of applications ranging from light emitting diodes (LEDs) and lasers to photovoltaics.
