Director of Photonics Application and Research Center
Gazi University, TR



Prof. Dr. Süleyman Özçelik is the founder and director of Photonics Application and Research Center of Gazi University. He is also head of Photonic Department of Applied Sciences Faculty of Gazi University. He has 20-years’ experience in conducting research and development activities for development of photonic devices, functional surfaces; is also experienced in modeling, designing, epitaxial growth, bulk single crystal growth, development of 3D and 2D thin films and space grade PV cell fabrication. He has conducted more than 30 projects in the field of advanced materials, semiconductor and photonic technologies. He has more than 200 articles published in international journals. Under his supervision, 20 PhD theses and more than 40 Master's theses have been completed. About 25 graduate students and post-doctoral researchers have been working in his directed projects that are currently underway.

​Presentation ​

Production of Single Crystal Germanium and Sapphire

​​​​Depending on the development of IR technology, IR optical materials such as Ge, Sapphire, Si, ZnSe, etc. have been used to production and design of plano-optics, aspherical, achromatic lenses and optical windows. In addition, some optical materials can be used production of domes for missile as well as armor windows in armed vehicles. Germanium having low band gap energy and high refractive index is a unique material for many electro-optical devices. The main applications of bulk monocrystalline germanium are optical lens and window in infrared systems, active material in gamma radiation detectors, and substrates for III - V based opto-electronic devices such as multi-junction solar cells, sensors. The Ge crystals can also be produced with having property of EMI shielding by increasing the conductivity during the growth process from the melt. Among the optical materials Sapphire is an ideal material for UV-Vis and IR applications since it has high optical transmission from 150 nm up to around 5µm. In addition, due to its excellent mechanical hardness, high thermal and chemical resistance, sapphire is a perfect material to production of the dome for missile as well as armor windows. Sapphire glasses are used in gas cryostats and helium microstats, metallic flanges as sealed or by sealing in the sockets of the devices. In addition, sapphire can be used optical material as watch smartphone windows and jewelry stone as well. In this talk, technological information about the studies carried out within the scope of bulk crystal growth in the Gazi Photonics Research Center and their applications of produced crystals will be presented.