ScienceAsia 32 (2006): 223-229 |doi: 10.2306/scienceasia1513-1874.2006.32.223

Growth and Characterization of Novel Optoelectronic Materials Based on II-VI Inorganic/Organic Heterostructures

Wisanu Pecharapa^*, Anusit Keawprajak, Nawapun Kayunkid, Sakon Rahong, Witoon Yindeesuk and Jiti Nukeaw

 
ABSTRACT: Novel optoelectronic materials based on II-VI inorganic/organic low-dimensional heterostructure were successfully grown by electron beam evaporator. The structures were based on ZnSe, tris(8- hydroxyquinoline) aluminum (Alq₃) and N,N’–bis(3-methylphenyl)-N,N’–diphenyl-benzidine (TPD). The surface morphology of the structures was investigated by atomic force microscopy and field emission scanning electron microscope. The optical and electronic properties were examined by photoluminescence, photocurrent and electroreflectance spectroscopy. Photoluminescence spectra of the ZnSe/Alq₃/ZnSe structure attributed to the change of exciton energy as a result of quantum confinement showed the formation of single quantum well structure. The luminescence color can be varied by changing the thickness of the Alq₃ layer. The other heterostructure of ZnSe/Alq₃/TPD was grown on silicon substrate. The wavelength response of this structure shown by photocurrent signal ranged from 450 nm to 1100 nm. Electroreflectance features due to optical transition energy of the single quantum well of this structure were also observed. Under applied voltage, electroreflectance signals showed significant shift due to the quantum confined Stark effect.

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Department of Applied Physics, Faculty of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand.

* Corresponding author, E-mail: Kpewisan@kmitl.ac.th

Received 16 Feb 2005, Accepted 8 Mar 2006