In present report, we investigated the degradation processes in porous silicon light-emitting devices (LED) in different atmospheres (O2, N2, air and vacuum) by photoluminescence (PL), electroluminescence (EL), lifetime (LT) and I-V characteristic measurements as well as by Energy Dispersive X-ray Spectroscopy (EDS). The contacts were made by evaporation of Au and Au/Cu alloy. The LEDs emit in visible range at forward and reverse bias. As a rule, full width at half maximum of EL spectrum is wider than that of PL spectrum. The bias direction of applied voltage during degradation change EL, PL, I-V characteristics, and LT of the LEDs. At forward bias, LT degradation is less than that in reverse bias.
The degradation of LEDs during forward bias did not produce any change in the spectral shape of EL and PL. At reverse bias, degradation led to red shift in the peak of EL and PL. The results show that the lifetime of LEDs with Au contact is longer than Au-Cu. Operating in different atmospheres, the LT in vacuum is longest and is more than 100 hours in reverse bias at room temperature.
Possible mechanisms of degradation of LEDs are discussed. It is proposed that degradation is connected mainly with two processes: oxidation and metal diffusion. It is shown that the oxygen and metal in ionic state can diffuse quickly. Hence, in forward bias, the diffusion of metal would dominate, and in reverse bias, diffusion of oxygen dominates.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
F. Kozlowski, P. Steiner, M. Sauter and W. Lang, J. Luminescence, 57, 185 (1993)
D. Dimova-Malinovska, M. Tzolov, N. Tzenov, D. Nesheva. Thin Sol. Films, 297, 285 (1997)
A. Loni, A.J. Simons, T.I. Cox, P.D.J. Calcott, L.T. Canham. Electron. Lett., 31, 1288 (1995)
A.J. Simons, T.I. Cox, A. Loni, L.T. Canham, M.J. Uren, C. Reeves, A.G. Gullis, P.D.J. Calcott, M.R. Houlton, J.P. Newey. In: Advanced Luminescent Materials, ed. By D.J. Lockwood, P.M. Fauchet, N. Koshida and S.R.J. Brueck, PV95-25, (Pennington, NJ, USA, 1996) p. 73.
L. Tsybeskov, S.P. Duttagupta, K.D. Hirschman, P.M. Fauchet. Appl. Phys. Lett., 68(15), 2058 (2058)
T. Oguro, H. Koyama, T. Ozaki, N. Koshida. J. Appl. Phys., 81(3), 1407 (1407)
US Patent., 60/364, 684
Ponpon J.P., Siffert P. J. Appl. Phys., 50(7), 5050 (5050)
M.A. Lamkin, F.L. Riley and R.J. Fordham, J. Eur. Ceram. Soc., 10, 347 (1992)
J. Zhang and I. Bowl, Appl. Phys. Lett., 71, 2964 (1997)
Y. Jin and K. Chang, Phys. Rev. Lett., 86, 1793 (2001)
The support of this work by Hong Kong Baptist University FRG grant is gratefully acknowledged.
About this article
Cite this article
Jumayev, B., Tam, H., Cheah, K. et al. Influence of Different Atmospheres on the Life Time of Porous Silicon Light-Emitting Devices. MRS Online Proceedings Library 737, 814 (2002). https://doi.org/10.1557/PROC-737-F8.14