3 research outputs found
Sequential Cation Exchange Generated Superlattice Nanowires Forming Multiple p–n Heterojunctions
Fabrication of superlattice nanowires (NWs) with precisely controlled segments normally requires sequential introduction of reagents to the growing wires at elevated temperatures and low pressure. Here we demonstrate the fabrication of superlattice NWs possessing multiple p–n heterojunctions by converting the initially formed CdS to Cu<sub>2</sub>S NWs first and then to segmented Cu<sub>2</sub>S–Ag<sub>2</sub>S NWs through sequential cation exchange at low temperatures. In the formation of Cu<sub>2</sub>S NWs, twin boundaries generated along the NWs act as the preferred sites to initiate the nucleation and growth of Ag<sub>2</sub>S segments. Varying the immersion time of Cu<sub>2</sub>S NWs in a AgNO<sub>3</sub> solution controls the Ag<sub>2</sub>S segment length. Adjacent Cu<sub>2</sub>S and Ag<sub>2</sub>S segments in a NW were found to display the typical electrical behavior of a p–n junction
Direct Synthesis and Practical Bandgap Estimation of Multilayer Arsenene Nanoribbons
Direct Synthesis and Practical Bandgap Estimation
of Multilayer Arsenene Nanoribbon
Plasma-Assisted Synthesis of High-Mobility Atomically Layered Violet Phosphorus
Two-dimensional layered materials
such as graphene, transition
metal dichalcogenides, and black phosphorus have demonstrated outstanding
properties due to electron confinement as the thickness is reduced
to atomic scale. Among the phosphorus allotropes, black phosphorus,
and violet phosphorus possess layer structure with the potential to
be scaled down to atomically thin film. For the first time, the plasma-assisted
synthesis of atomically layered violet phosphorus has been achieved.
Material characterization supports the formation of violet phosphorus/InN
over InP substrate where the layer structure of violet phosphorus
is clearly observed. The identification of the crystal structure and
lattice constant ratifies the formation of violet phosphorus indeed.
The critical concept of this synthesis method is the selective reaction
induced by different variations of Gibbs free energy (Δ<i>G</i>) of reactions. Besides, the Hall mobility of the violet
phosphorus on the InP substrate greatly increases over the theoretical
values of InP bulk material without much reduction in the carrier
concentration, suggesting that the mobility enhancement results from
the violet phosphorus layers. Furthermore, this study demonstrates
a low-cost technique with high compatibility to synthesize the high-mobility
atomically layered violet phosphorus and open the space for the study
of the fundamental properties of this intriguing material as a new
member of the fast growing family of 2D crystals