Nanoscale ZnO-Enhanced/Si Heterojunction Pure/Stable Blue Light Emitting Diode
S. Fiat Varol
1*
, M. Kompitsas
2
, Derya Unal
3
, Ziya Merdan
3
, D.E. Manolakos
4
,
P. Koralli
2
,4
1
Giresun University, Faculty of Engineering, Energy Systems Engineering, 28200, Giresun,
Turkey
2
National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48
Vasileos Constantinou Avenue,11635 Athens, GREECE
3
Gazi University, Faculty of Arts and Sciences, Physics Department, 06500 Ankara, Turkey
4
School of Mechanical Engineering, National Technical University of Athens, Iroon
Polytechniou 9 Zografu, 15780 Athens, GREECE
E-mail:
We reported a pure/stable a p–n heterojunction ZnO/Si LED with different oxygen pressures
(10-50Pa), fabricated by Pulsed Laser Deposition. Here in this work, we demonstrated the
capability of controlling the spatial distribution of the blue/near-UV LEDs composed of
position controlled arrays of n-ZnO nanocrystals on a p-Si thin film substrate. The devices
exhibited a strong responsivity in the blue region at 448, 455, 470 and 488 nm wavelengths.
Control over the size, shape, surface roughness, and crystallization is of great significance for
the fabrication of ZnO materials since they affect their performance in practical applications.
Due to this, ZnO has been introduced into conventional Si-based LEDs to enhance the light
extraction efficiency (LEE). It was found that ZnO micro/nano rods with needle-like or flat
end modified LEDs possess much higher LEE. It was found that the device performance is
strongly dependent on the oxygen pressure amount.
The electroluminescence (EL) has been extensively studied and emission spectrum of the as-
fabricated LED was monitored at different biased voltages/injection-currents at room
temperature. We saw that, from 5.3 V to 12 V, the contour of the EL spectrum does not
change much with the biased voltage. The dominant emission peak is slightly blue shifted in
the range of 450 nm–490 nm with a full width at half maximum (FWHM) of about 64 nm.
Keywords: ZnO; Si; Pulsed Laser Deposition; Light Emitting Diode (LED), PL; EL.
PS1 14
-170-
