High-efficiency color tunable n-CdSxSe1−x/p+-Si parallel-nanobelts heterojunction light-emitting diodes

Abstract

In this manuscript, n-type CdS_xSe_1−x nanobelts (NBs) with the entire composition range were synthesized via a simple Cd-riched chemical vapor deposition method. Moreover, using the n-CdS_xSe_1−x alloy NBs and p⁺-Si NBs as representative building blocks, novel high-efficiency color tunable parallel-nanobelts heterojunction light-emitting diodes (PNBs-HLEDs) were fabricated and studied for the first time, where the two nanobelts forming the heterojunction were face-contacted and parallel to each other. Compared with previously reported nano-LEDs, where the active region was near point-shaped, the PNBs-HLEDs here have the advantages of larger active region, smaller series resistance, higher electron and hole injective current, and lower turn-on voltage. Intense room-temperature electroluminescence with a wide range of color (from 510–708 nm) was observed from the n-CdS_xSe_1−x/p⁺-Si PNBs-HLEDs. The novel device structure together with the well-developed CdS_xSe_1−x NB growth and doping method promises a bright future for the CdS_xSe_1−x based PNBs-HLEDs in various nano-device applications, such as electrically driven lasers, multi-color displays, white light illumination etc. Besides, the approach to fabricating PNBs-HLEDs should be easy to extend to other material system.