Dr. A.H. Kitai

Professor
Department of Engineering Physics*

McMaster University
1280 Main Street West, Hamilton
Ontario, Canada  L8S 4L7

office: JHE/A322
email:  kitaia@mcmaster.ca
voice:  (905) 525-9140 x 24973
fax:    (905) 527-8409

*Cross appointed with Material Science & Engineering

B.Eng. (McMaster), Ph.D. (Cornell)

Research Interests

1) Fundamental luminescent materials
Visible emission from oxide phosphor materials Zn2Si04:Mn, Ga203:Eu and related compounds is being studied under electroluminescence, photoluminescence and cathodoluminescence.
Thin films of these oxide phosphors are being grown by RF sputtering, on glass and ceramic substrates. Defects in II-VI phosphors are being studied to determine the relationship between point defects and luminescence in these materials.

This work shows for the first time that thin films of oxide phosphors can achieve bright EL emission using thin film dielectrics on smooth substrates.

Commercial brightness and efficiency values achieved on glass substrates with the new green phosphor achieved stable operation of Zn2Si0.5Ge0.5O4:Mn thin films paving the way for industrial use of these materials.

2) New luminescent devices
A new and unique type of luminescent “Sphere Supported Thin Film Electroluminescent” (SSTFEL) device has been developed. This involves spherical ceramic particles coated with a thin film semiconductor phosphor material, and then embedded in a polymer sheet.
Flexible light emitting sheets are enabled, which are capable of long life, high brightness performance. A photograph of a recent prototype is shown below:

3) New avalanche injection Devices

Two new research projects involve avalanche-injection electroluminescence. Here, electrons are injected into a semiconductor using high electric fields. High efficiency and low voltage EL devices suitable for flexible display devices may be realized by this research. Two PhD student projects on this are being started.

4/ Optical Fiber Liquid Crystal Display Technology:

A new type of display using the combination of a uniquely woven optical fiber array, light emitting diodes, and liquid crystal-based light modulation achieves an intense full colour display suitable for public information in the form of an electronic poster. New optical components are being developed to optimize the performance of this system.

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Publications

A.H. Kitai, Y. Xiang, G. Quan, F. Zhang, Q. Liu, “Sphere-Supported Thin Film Electroluminescent Technology”, Proc. EL2004, 347-350, 2004

Y. Xiang, A. H. Kitai “Sphere-Supported Thin Film Electroluminescence, Properties and Modelling”, Proc. EL2004, pp314-316, and p366.

A.H. Kitai, "Oxide Phosphor and Dielectric Thin Films For Electroluminescent Devices", Thin Solid Films 445, 367-376, 2003

G. Stuyven, P. De Visschere, K. Neyts, A.H. Kitai, "Characterization of the electro-optical behaviour of Zn2Si0.5Ge0.5O4:Mn thin film electroluminescent devices", Journal of Applied Physics, 93, 4622-4627, April 2003

A.H. Kitai, Y. Xiang, G. Quan, F. Zhang,Q. Liu, B. Cox, “Sphere-Supported Thin Film Electroluminescent Technology, SID Int’l Symp Dig,SID 04 Digest 558-561, 2004

A.H. Kitai, K.A. Cook and W. Tait, “Capacitively Switched Matrixed AC EL Display”, Proc. 2002 Intl. Conf., Sci. & Tech. Of Emissive Displays and Lighting, pp. 343-345, Sept. 2002

A.H. Kitai, S. Li, D.V. Stevanovic, J. Deng and K. A. Cook, “Electric Field
Enhancement for Oxide Phosphor Thin Film EL Devices”, Proc. 2002 Intl. Conf.,
Sci. & Tech. Of Emissive Displays and Lighting, pp. 311-314, Sept. 2002

M. Flynn, A.H. Kitai, "New (CdxZn1?x)Ga2O4:Mn Green Emitting Phosphors for EL Displays", accepted for SID International Symposium Digest, Feb. 2002.

A.H. Kitai, X. Deng, D. Stevanovic, Z. Jiang, S. Li, N. Peng, B.F. Collier, K. Cook, "High Performance Dielectric Layer for Thin Film Oxide Phosphor Electroluminescent Devices", accepted for SID International Symposium Digest, Feb. 2002.

A.H. Kitai, Y. Zhang, D. Ho, D.V. Stevanovic, Z. Huang, A. Nakua, K.A. Cook, "Oxide Phosphor Green EL Devices on Glass Substrates", SID Int'l. Symp. Dig., Vol. 30, pp. 596-599, May 1999.

T. Xiao, A.H. Kitai, G. Liu, A. Nakua, "Bright Green Oxide Phosphors for Electroluminescent Displays", SID International Symposium Dig, 28, 415-418, Boston, May 13-15, 1997.

A.H. Kitai, T. Xiao, G. Liu, J.H. Li, "Dopes Amorphous and Crystalline Gallium Oxides and Alkaline Earth Gallates as EL Materials", SID Int'l. Symp Dig., Vol. 28, pp. 419-422, May 13-15, 1997.

T. Xiao, A.H. Kitai, J. Barbier, "Thin Film Electroluminescence in Highly Anisotropic Oxide Materials", Applied Physics Letters, 72, 3356-3358 (1998).

T. Xiao, G. Liu, M. Adams, A.H. Kitai, "Green Zn ₂SiO₄ Thin Film Electroluminescence on Silicon Substrates", Can. J. Phys. 74, 132-135 (1996).