3 research outputs found
Direct Synthesis and Practical Bandgap Estimation of Multilayer Arsenene Nanoribbons
Direct Synthesis and Practical Bandgap Estimation
of Multilayer Arsenene Nanoribbon
Enhanced Conversion Efficiency of Cu(In,Ga)Se<sub>2</sub> Solar Cells via Electrochemical Passivation Treatment
Defect control in CuÂ(In,Ga)ÂSe<sub>2</sub> (CIGS) materials, no matter what the defect type or density,
is a significant issue, correlating directly to PV performance. These
defects act as recombination centers and can be briefly categorized
into interface recombination and Shockley–Read–Hall
(SRH) recombination, both of which can lead to reduced PV performance.
Here, we introduce an electrochemical passivation treatment for CIGS
films that can lower the oxygen concentration at the CIGS surface
as observed by X-ray photoelectron spectrometer analysis. Temperature-dependent <i>J–V</i> characteristics of CIGS solar cells reveal that
interface recombination is suppressed and an improved rollover condition
can be achieved following our electrochemical treatment. As a result,
the surface defects are passivated, and the power conversion efficiency
performance of the solar cell devices can be enhanced from 4.73 to
7.75%
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