Chemical Tailoring of Band Offsets at the Interface of ZnSe–CdS Heterostructures for Delocalized Photoexcited Charge Carriers
| Autor: | Somobrata Acharya, Amit Dalui, D. D. Sarma, Indra Dasgupta, Sucheta Sengupta, Umamahesh Thupakula, Arup Lal Chakraborty, Biswarup Satpati, Ali Hossain Khan |
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| Rok vydání: | 2016 |
| Předmět: |
Valence (chemistry)
Materials science business.industry Band gap Heterojunction 02 engineering and technology Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 010402 general chemistry 021001 nanoscience & nanotechnology Epitaxy 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Photoexcitation Condensed Matter::Materials Science Delocalized electron General Energy Quantum dot Optoelectronics Charge carrier Physical and Theoretical Chemistry 0210 nano-technology business |
| Zdroj: | The Journal of Physical Chemistry C. 120:10118-10128 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/acs.jpcc.6b00986 |
| Popis: | Monocomponent quantum dots (QDs) possess limited electron–hole delocalization capacity upon photoexcitation that suppresses the efficiency of photoenergy harvesting devices. Type II heterostructures offer band offsets at conduction and valence bands depending upon the band gaps of the constituent QDs which largely depend on their sizes. Hence, by keeping the size of one constituent QD fixed while varying the size of the other QD selectively, the band offsets at the interface can be engineered selectively. We report on the tuning of band offsets by synthesizing component size modulated heterostructures composed of a fixed sized ZnSe QD and size tuned CdS QDs with variable band gaps. The resultant heterostructures show spontaneous charge carrier separation across the interface upon photoexcitation depending on the extent of band offsets. Formation mechanism, epitaxial relationship, and the intrinsic nature of interface of the heterostructures are investigated. Experimental results are corroborated with ab i... |
| Databáze: | OpenAIRE |
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