1. II-VI Semiconductor Materials, Devices, and Applications
Tony Stein
EE 4611

2. Overview List of II-VI Semiconductor Materials General Properties
Applications of Each Compound
Overview/Conclusion
References
Key Points

3. Common II-VI Compounds
Zinc Oxide
Zinc Sulfide
Zinc Selenide
Zinc Telluride
Cadmium Sulfide
Cadmium Selenide
Cadmium Telluride

4. Advantages Wide Band Gap ranging from 1.5 eV to 3.54 eV
Compare to Si Band Gap of 1.1 eV
Wide Band Gap allows devices to operate at much higher voltages, frequencies and temperatures
Higher Breakdown Voltage = High Power & Frequency Applications Higher Doping Concentration = Thinner Device Layers Higher Electron Mobility = Faster Operation

5. Cadmium Sulfide (CdS) Conductivity increases when exposed to light
Leading to use as a photoresistor
It forms the core component of a solar cell

6. Cadmium Sulfide (CdS) Cont.
Piezoelectric and Pyroelectric capabilities
CdS crystal can act as a solid state laser
Electroluminescence capabilities
fabtolab.com

7. http://www. creationscience

8. Cadmium Selenide (CdSe)
Applications: Solar Cells, LEDs, Biomedical Imaging
Much of the current research on cadmium selenide is focused on its nanoparticles

9. Cadmium Selenide (CdSe) Cont.
One type of CdSe nanoparticle is a CdSe quantum dot
Quantum dots are small semiconductor particles
Will emit light of specific frequencies if electricity or light is applied to them
These frequencies can be precisely tuned by changing the dots size and shape, giving rise to many applications.

10. Potential applications include transistors, solar cells, LEDs, diode lasers

11. http://ffden-2. phys. uaf. edu/631fall2008_web

12. Cadmium Telluride (CdTe)
CdTe can be alloyed with mercury to make an infrared detector material (HgCdTe)
CdTe doped with chlorine is used as a radiation detector for x-rays, gamma rays, beta particles and alpha particles
Used to make Thin Film solar cells

13. Cheaper but less efficient than conventional photovoltaic technology.
Film thickness varies from a few nanometers to tens of micrometers - Much thinner than 1st generation PV -(200µm)
Cheaper but less efficient than conventional
photovoltaic technology.
Faster degradation compared to
conventional PV

14. Zinc Oxide (ZnO) Transparent thin-film Transistors Photodetectors LEDs
Laser Diodes

15. Zinc Sulfide (ZnS)
Zinc Sulfide can be transparent and used as a window for visible optics and infrared optics
Used in Electroluminescent Panels

16. Zinc Selenide (ZnSe) LEDs, Diode Lasers X-ray and gamma ray detectors
Luminescent
Infrared Optical Material
visiblediodelasers.com

17. Zinc Telluride (ZnTe)
Optoelectronics
LEDs
Laser Diodes
Solar Cells

18. Summary
II-VI semiconductor materials are becoming increasingly important in the semiconductor industry. These compounds are integrating themselves into modern electronics and replacing conventional silicon in certain applications. While it’s impossible to determine just how large of an effect these materials will have and how long-lived they will be, high power electronics, the military, and the medical industry are already benefiting from them.

19. References
D. Lincot, Gary Hodes Chemical Solution Deposition of Semiconducting and Non-Metallic Films: Proceedings of the International Symposium The Electrochemical Society, 2006 ISBN
H. Zhao et al, "The effect of impurities on the doping and VOC of CdTe/CdS thin film solar cells", Thin Solid Films, Vol. 517, No. 7 (2009) pp , [1] doi: /j.tsf
Minkus, Wilfred (1965). "Temperature Dependence of the Pyroelectric Effect in Cadmium Sulfide". Physical Review. 138 (4A): A1277. Bibcode:1965PhRv M. doi: /PhysRev.138.A1277.
Robel, I.; Subramanian, V.; Kuno, M.; Kamat, P.V. (2006). "Quantum Dot Solar Cells. Harvesting Light Energy with CdSe Nanocrystals Molecularly Linked to Mesoscopic TiO2 Films". J. Am. Chem. Soc. 128: 2385–2393. doi: /ja056494n.

20. References
Bakin, A.; et al. (2010). "ZnO – GaN Hybrid Heterostructures as Potential Cost Efficient LED Technology". IEEE (Invited Paper for a special volume), Proceedings of the IEEE. 98 (7): 1281– doi: /JPROC
Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p ISBN
Kittel, C. (1976) Introduction to Solid State Physics, 5th edition, p. 28.
Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN
Efros, Al. L.; Rosen, M. (2000). "The electronic structure of semiconductor nanocrystals". Annual Review of Materials Science. 30: 475–521. Bibcode:2000AnRMS E. doi: /annurev.matsci

21. References
Chalcogenide Photovoltaics: Physics, Technologies, and Thin Film Devices by Scheer and Schock, page 6. Link (subscription required). "Nowadays, CdTe modules are produced on the GWp/year level and currently are the cost leader in the photovoltaic industry."

22. Key Topics Common Compounds of II-VI Semiconductors
Advantages of Wide Band Gap semiconductors
Quantum Dots will emit light of specific frequencies if electricity or light is applied to them
How does a piezoelectric transducer work?
Thin film Solar cells are cheaper but less efficient than silicon solar cells