Applications
Cadmium selenide in its wurtzite crystal structure is an important II-VI semiconductor. As a semiconductor CdSe is an n-type semiconductor, which is difficult to dope p-type, however p-type doping has been achieved using nitrogen. CdSe is also being developed for use in opto-electronic devices, laser diodes, nanosensing, and biomedical imaging. They are also used being tested for use in high-efficiency solar cells CdSe is also a suitable material for making thin-film transistors (TFTs). TFTs made from this material were used in the first active-matrix liquid-crystal display showing a still picture in 1973. However interest in CdSe for this application largely waned after the emergence of amorphous silicon technology in the late 1970s.
Most of the usefulness of CdSe stems from nanoparticles, that is particles with sizes below 100 nm. CdSe particles of this size exhibit a property known as quantum confinement. Quantum confinement results when the electrons in a material are confined to a very small volume. Quantum confinement is size dependent, meaning the properties of CdSe nanoparticles are tunable based on their size.
Since CdSe nanoparticles have a size dependent fluorescence spectrum, they are finding applications in optical devices such as laser diodes. Using these particles, engineers are able to manufacture laser diodes that cover a large part of the electromagnetic spectrum.
Along similar lines, doctors are developing these materials for use in biomedical imaging applications. Human tissue is permeable to far infra-red light. By injecting appropriately prepared CdSe nanoparticles into injured tissue, it may be possible to image the tissue in those injured areas.
Read more about this topic: Cadmium Selenide