J. Phys. Colloques
Volume 42, Numéro C4, Octobre 1981Proceedings of the Ninth International Conference on Amorphous and Liquid Semiconductors
|Page(s)||C4-317 - C4-322|
J. Phys. Colloques 42 (1981) C4-317-C4-322
ACTIVE AND PASSIVE STUDIES OF AMORPHOUS CHALCOGENIDE IR EMITTERSP.J. Walsh1, A. Jaafar2, M.J. Thompson2 and D. Adler3
1 Fairleigh Dickinson University, Teaneck, NJ 07666, U.S.A.
2 The University of Sheffield, Sheffield S1 3JD, United Kingdom
3 Massachusetts Institute of Technology, Cambridge, Mass., 02139, U. S. A.
Optical properties of thin-film light-emitting amorphous diodes of Si18Te45As28Ge9 have been measured both at the University of Sheffield and at MIT. We determined the wavelength dependence of the refractive index of the deposited glass, the passive external interference mode structure of the fabricated devices with reflecting lower contacts and semi transparent upper contacts and the corrected infrared emission spectrum on the same devices. At currents just above the optical threshold in the on-state the emission is narrow band, at a wavelength consistent with earlier experiments, while at higher currents the emission shows the narrow component with a broad component which follows the shape of the passive external transmittance. The optical threshold current of these types of devices increases with increased thickness of the transparent upper contact indicating the optical feedback requirement of this emission. The various results we have obtained reinforce the presumption that the emission is stimulated.