White Light Emission from Black Germanium

Shinde, Satish Laxman and Dao, Thang Duy and Ishii, Satoshi and Nien, Li-Wei and Nanda, Karuna Kar and Nagao, Tadaaki (2017) White Light Emission from Black Germanium. In: ACS PHOTONICS, 4 (7). pp. 1722-1729.

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Abstract

We demonstrate the nearly perfect absorption and quantum dots-mediated enhanced visible light emissions from defect engineered Ge nanopyramids or black germanium. High-resolution 3D photoluminescence (PL) imaging of the pyramid structure elucidated the position dependency of defects and their emission: Stronger photoluminescence yield was observed at the nanopyramid tips, which is correlated to the efficient light nanofocusing at the tips where increased defect density and roughness at the interface between Ge and surface oxide (GeO2) also takes place. Furthermore, the visible light emissions from this GeO2/Ge interface can be enhanced,similar to 15-fold when CdTe quantum dots (QDs) are adsorbed on the GeO2/Ge system. The enhanced luminescence of our structure can be attributed to the extraordinary light harvesting property of pyramid structure; strong antireflection effect, pronounced defect formation at the nanopyramid tips, and anomalous resonant energy transfer between GeO2 defects and CdTe QDs. The proposed methodology can be applied to other nanostructured wide bandgap materials to turn them into solar light harvesters and bright white light-emitting phosphors.

Item Type:	Journal Article
Publication:	ACS PHOTONICS
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	12 Aug 2017 06:44
Last Modified:	12 Aug 2017 06:44
URI:	http://eprints.iisc.ac.in/id/eprint/57617

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