chemistry

II-VI semiconductor compound

II-VI semiconductor compound is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand II-VI semiconductor compound rather than just read about it. In short: II-VI semiconductor compounds are compounds composed of a metal from either group 2 or 12 of the periodic table (the alkaline earth metals and group 12 elements, formerly called groups IIA and IIB) and a nonmetal from group 16 (the chalcogens, formerly called group VI). These semiconductors crystallize either in the zincblende lattice structure or the wurtzite crystal structure.

Key takeaways

II-VI semiconductor compound belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect II-VI semiconductor compound to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of II-VI semiconductor compound from memory before moving on to harder problems.

Reference excerpt

II-VI semiconductor compounds are compounds composed of a metal from either group 2 or 12 of the periodic table (the alkaline earth metals and group 12 elements, formerly called groups IIA and IIB) and a nonmetal from group 16 (the chalcogens, formerly called group VI). These semiconductors crystallize either in the zincblende lattice structure or the wurtzite crystal structure. They generally exhibit large band gaps, making them popular for short wavelength applications in optoelectronics.

Fabrication

II-VI semiconductor compounds are produced with epitaxy methods, like most semiconductor compounds. The substrate plays an important role for all fabrication methods. Best growth results are obtained by substrates made from the same compound (homoepitaxy), but substrates of other semiconductors are often used to reduce the fabrication cost (a method called heteroepitaxy). In particular, III-V semiconductor compounds like gallium arsenide are frequently used as cheap substrates, resulting in stronger tensions between substrate and growth layer and (generally) lower optoelectronic properties.

Properties Especially wide bandgap II-VI semiconductor compounds are expected to be very good candidates for high performance applications, such as light emitting diodes and laser diodes for blue and ultraviolet applications. Due to problems with conductivity, the application of these materials is still questionable. The best example is zinc oxide, which shows excellent optical characteristics, though it remains problematic to create sufficient charge carrier densities via doping in zinc oxide.

Ternary compounds are one option to vary the band gap of semiconductors almost continuously over a wide energy range. This method is highly dependent on the materials as well as the growth techniques. In particular, materials with very different lattice constants or different crystal phases (wurtzite or zincblende in this case) are difficult to combine. Tensions and impurities due to low crystal quality result in low optoelectronic properties. One example of the basic possibilities achievable with three different compounds is shown in the diagram with zinc oxide (ZnO), cadmium oxide (CdO) and magnesium oxide (MgO). Basically it is possible to gain any band gap between those of the three materials. Consequently, it is possible to choose very specifically the wavelength of photons emitted by laser diodes or light emitting diodes.

See also Wide-bandgap semiconductor List of semiconductor materials

References

External links https://www2.warwick.ac.uk/fac/sci/physics/current/postgraduate/regs/mpags/ex5/intro/groupii-vi/

Illustrations

Worked examples

Example 1 — a first encounter with II-VI semiconductor compound

Start with the simplest possible case. Write down what II-VI semiconductor compound claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to II-VI semiconductor compound before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about II-VI semiconductor compound ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of II-VI semiconductor compound

In research: II-VI semiconductor compound appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses II-VI semiconductor compound in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: II-VI semiconductor compound is common in secondary-school and first-year university syllabi. It links to neighbouring topics II-VI semiconductors, so understanding it makes those chapters shorter.
In everyday life: Look for II-VI semiconductor compound outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study II-VI semiconductor compound in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what II-VI semiconductor compound means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain II-VI semiconductor compound out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is II-VI semiconductor compound in simple terms?

Why does II-VI semiconductor compound matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study II-VI semiconductor compound?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on II-VI semiconductor compound.