An efficient Si light-emitting diode based on an n- ZnO/SiO2-Si nanocrystals-SiO2/p-Si heterostructure.
Si nanocrystals embedded in a SiO2 matrix and an n-type Al-doped ZnO (ZnO:Al) layer were applied to improve the external quantum efficiency from Si in n- ZnO/SiO2-Si nanocrystals-SiO2/p-Si heterojunction light-emitting diodes (LEDs). The Si nanocrystals were grown by low pressure chemical vapor deposition and the ZnO:Al layer was prepared by atomic layer deposition. The n-type ZnO:Al layer acts as an electron injection layer, a transparent conductive window, and an anti-reflection coating to increase the light extraction efficiency. Owing to the spatial confinement of carriers and surface passivation by the surrounding SiO2, the Si nanocrystals embedded in the SiO2 matrix lead to a significant enhancement of the light emission efficiency from Si. An external quantum efficiency up to 4.3 x 10(-4) at the wavelength corresponding to the indirect bandgap of Si was achieved at room temperature.
Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, Republic of China.
Edward
E
Sun
Fu-Hsiang
FH
Su
Ying-Tsang
YT
Shih
Hung-Ling
HL
Tsai
Ching-Huang
CH
Chen
Mong-Kai
MK
Wu
Jer-Ren
JR
Yang
Miin-Jang
MJ
Chen