Thickness-Tunable Self-Assembled Colloidal Nanoplatelet Films Enable Ultrathin Optical Gain Media
Nano Letters, cilt.20, sa.9, ss.6459-6465, 2020 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 20 Sayı: 9
- Basım Tarihi: 2020
- Doi Numarası: 10.1021/acs.nanolett.0c02153
- Dergi Adı: Nano Letters
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC, MEDLINE
- Sayfa Sayıları: ss.6459-6465
- Anahtar Kelimeler: liquid interface self-assembly, colloidal nanoplatelets, planar waveguides, optical gain, amplified spontaneous emission
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
We propose and demonstrate construction of highly uniform, multilayered superstructures of CdSe/CdZnS core/shell colloidal nanoplatelets (NPLs) using liquid interface self-assembly. These NPLs are sequentially deposited onto a solid substrate into slabs having monolayer-precise thickness across tens of cm2 areas. Because of near-unity surface coverage and excellent uniformity, amplified spontaneous emission (ASE) is observed from an uncharacteristically thin film having 6 NPL layers, corresponding to a mere 42 nm thickness. Furthermore, systematic studies on optical gain of these NPL superstructures having thicknesses ranging from 6 to 15 layers revealed the gradual reduction in gain threshold with increasing number of layers, along with a continuous spectral shift of the ASE peak (∼18 nm). These observations can be explained by the change in the optical mode confinement factor with the NPL waveguide thickness and propagation wavelength. This bottom-up construction technique for thickness-tunable, three-dimensional NPL superstructures can be used for large-area device fabrication.