Blue-Green Light Emission From Si and SiC Quantum Dots Co-Doped Si-Rich SiC [Formula Omitted] Junction Diode

• Published in: IEEE journal of selected topics in quantum electronics 2014-07, Vol.20 (4), p.1
• Main Authors: Tai, Hung-Yu, Cheng, Chih-Hsien, Lin, Gong-Ru
• Format: Article
• Language: English
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2013.2291701

Si quantum dots and SiC quantum dots (SiC-QDs) co-doped Si-rich silicon carbide (Si [Formula Omitted]C[Formula Omitted]) based [Formula Omitted] junction light-emitting diodes (LEDs) with blue light emission is demonstrated. By growing the Si[Formula Omitted]C [Formula Omitted] with plasma-enhanced chemical vapor deposition at relatively low temperature, the turn-on voltage of Si-rich Si[Formula Omitted] C[Formula Omitted] LEDs can be reduced to 6.1 V when thinning [Formula Omitted]-Si[Formula Omitted]C [Formula Omitted] layer to 25 nm because of higher tunneling probability and lower series resistance. The electroluminescent (EL) power increases to 136 nW, however, which inversely attenuates due to the reduced SiC-QDs if the [Formula Omitted]-Si [Formula Omitted]C[Formula Omitted] thickness further shrinks to 25 nm. The principle EL peak at 500 nm with narrower shape and blue-green emission pattern is attributed to the self-trapped excitons at surface states among SiC-QDs. The external quantum efficiency (EQE) of the Si-rich Si[Formula Omitted]C [Formula Omitted] LEDs with i-Si[Formula Omitted]C[Formula Omitted] thickness of 50 nm is up to 1.58 × 10[Formula Omitted]% with enhanced carrier tunneling probability. The carrier injection efficiency is enhanced to 46% by increasing the doping concentration to 10 [Formula Omitted] cm[Formula Omitted], leading to almost one order of magnitude improvement on the EQE of Si-rich Si[Formula Omitted]C[Formula Omitted] LEDs.