Boosting Enhancement of the Electron–Phonon Coupling in Mixed Dimensional CdS/Graphene van der Waals Heterojunction

Abstract

Electron–phonon coupling plays a key role in affecting the properties of the semiconducting nanostructures, such as providing the possibility for obtaining higher superconducting transition temperatures. Here, using Raman, temperature‐dependent and polarized Raman scattering measurements, ultra‐strong electron–phonon coupling in 1D CdS nanowires and 2D graphene heterostructures is demonstrated. The intensity ratio of 2LO/1LO mode in CdS nanowires provides a spectroscopy‐based method to quantify electron–phonon coupling, the strength of which is temperature and polarization dependent. The intensity ratio mode of 2LO/1LO in heterostructure reached up to 8.95 when the incident laser polarization is parallel to the c‐axis of the nanowire. It is ≈2.37 times higher than in an individual nanowire. In addition, in situ and time‐resolved photoluminescence spectra demonstrate the dynamics of the exciton recombinations, providing a comprehensive understanding of the enhancement of electron–phonon coupling in heterostructures. Via optical waveguiding characterization, the graphene layer is demonstrated to not only be an ultrafast carrier transfer channel but also a low Fermi level channel that induces the formation of the built in electrical field, elevating the electron–phonon coupling. Such new mixed dimensional heterostructures illustrate a straightforward approach to enhance the electron–phonon coupling, which may be applied to many integrated superconducting photonic and optoelectronic devices.

Atomically Precise Metal Nanoclusters versus Metal Nanocrystals: Maneuvering Tunable Charge Transfer in an Integrated Photosystem

“…The increased I 2LO /I 1LO ratio suggests that Ag x @ GSH NCs and Ag NYs play important roles in enhancing excition−phonon coupling in CdS NWs. 30,31 In addition, the signal intensity of Ag x @GSH/CdS and Ag/CdS is much lower than that of the CdS NW substrate, indicative of the successful deposition of Ag x @GSH NCs and Ag NYs on the CdS substrate, thus shielding the CdS signal.…”

“…Compared with pristine CdS NWs ( I 2LO / I 1LO = ca 0.53), the intensity ratio of 2LO/1LO in the Ag x @GSH/CdS and Ag/CdS heterostructures is markedly elevated (i.e., 0.71, 0.62, 0.86, and 0.88 for 5-Ag x @GSH/CdS, 5-Ag/CdS, 40-Ag x @GSH/CdS, and 40-Ag/CdS, respectively). The increased I 2LO / I 1LO ratio suggests that Ag x @GSH NCs and Ag NYs play important roles in enhancing excition–phonon coupling in CdS NWs. , In addition, the signal intensity of Ag x @GSH/CdS and Ag/CdS is much lower than that of the CdS NW substrate, indicative of the successful deposition of Ag x @GSH NCs and Ag NYs on the CdS substrate, thus shielding the CdS signal.…”

Transport Property of Wrinkled Graphene Nanoribbon Tuned by Spin-Polarized Gate Made of Vanadium-Benzene Nanowire

“…So far, numerous researchers have strongly demonstrated that vdWHs based on graphene are the most promising materials for potential applications in electronic and optoelectronic fields. Generally, graphene could form various vdWHs with zero-dimensional (0D) quantum dots and plasmonic nanoparticles such as Ag nanoparticles [10,11], one-dimensional (1D) nanoribbons and nanowires such as CdS nanowires, carbon nitride sheet [12,13], as well as two-dimensional (2D) nanomaterials such as hexagonal boron nitride, layered transition metal dichalcogenides and metal oxides [14][15][16][17][18][19][20][21], referred to as 0D-G, 1D-G, and 2D-G vdWHs, respectively. Especially, the 1D-G vdWHs have already been used to fabricate many transistors with high speed and flexibility by using the 1D structure as a gate [22,23].…”