Electrodeposited Light-Emitting Nanojunctions
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- 作者：Wendong Xing ; Wenbo Yan ; Talin Ayvazian ; Yong Wang ; Eric O. Potma ; Reginald M. Penner
- 刊名：Chemistry of Materials
- 出版年：2013
- 出版时间：February 26, 2013
- 年：2013
- 卷：25
- 期：4
- 页码：623-631
- 全文大小：661K
- 年卷期：v.25,no.4(February 26, 2013)
- ISSN：1520-5002
文摘
Electroluminescent (EL) metal-semiconductor-metal nanojunctions are prepared by electrodepositing nanocrystalline cadmium selenide (nc-CdSe) within 250 nm gold (Au) nanogaps prepared by focused ion beam milling. The electrodeposition of nc-CdSe is carried out at two temperatures: 20 掳C (鈥渃old鈥? and 75 掳C (鈥渉ot鈥?, producing mean grain diameters of 6 卤 1 nm and 11 卤 2 nm, respectively, for the nc-CdSe. Light-emitting nanojunctions (LEnJs) prepared at both temperatures show a low threshold voltage for light emission of <2 V; just above the 1.74 eV bandgap of CdSe. The EL intensity increases with the injection current and hot-deposited LEnJs produced a maximum EL intensity that is an order of magnitude higher than the cold-deposited LEnJs. Emitted photons are bimodal in energy with emission near the band gap of CdSe, and also at energies 200 meV below it; consistent with a mechanism of light emission involving the radiative recombination of injected holes with electrons at both band-edge and defect states. The quantum yield for 鈥渉ot鈥?electrodeposited nc-CdSe LEnJs is comparable to devices constructed from single crystalline nanowires of CdSe, and the threshold voltage of 1.9 (卤0.1) V (cold) and 1.5 (卤0.2) V (hot) is at the low end of the range reported for CdSe nanowire based devices.