Modification of the spontaneous emission of quantum dots near the surface of a three-dimensional colloidal photonic crystal

• Published in: Chinese physics B Vol. 19; no. 11; pp. 441 - 447
• Main Author: 刘正奇 冯天华 戴峭峰 吴立军 兰胜 丁才蓉 汪河洲 Gopal Achanta Venu
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.11.2010
• Subjects: 三维光子晶体; 半导体量子点; 数值模拟; 晶体表面; 演示实验; 自发辐射
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/11/114210

This paper demonstrates experimentally and numerically that a significant modification of spontaneous emission rate can be achieved near the surface of a three-dimensional photonic crystal. In experiments, semiconductor coreshell quantum dots are intentionally confined in a thin polymer film on which a three-dimensional colloidal photonic crystal is fabricated. The spontaneous emission rate of quantum dots is characterised by conventional and time-resolved photoluminescence （PL） measurements. The modification of the spontaneous emission rate, which is reflected in the change of spectral shape and PL lifetime, is clearly observed. While an obvious increase in the PL lifetime is found at most wavelengths in the band gap, a significant reduction in the PL lifetime by one order of magnitude is observed at the short-wavelength band edge. Numerical simulation reveals a periodic modulation of spontaneous emission rate with decreasing modulation strength when an emitter is moved away from the surface of the photonic crystal. It is supported by the fact that the modification of spontaneous emission rate is not pronounced for quantum dots distributed in a thick polymer film where both enhancement and suppression are present simultaneously. This finding provides a simple and effective way for improving the performance of light emitting devices.