We report an analysis method that combines microphotoluminescence mapping and lifetime mapping data of single semiconductor nanowires to extract the doping concentration, nonradiative lifetime, and internal quantum efficiency along the length of the nanowires. Using this method, the doping concentration of single Si-doped wurtzite InP nanowires are mapped out and confirmed by the electrical measurements of single nanowire devices. Our method has important implication for single nanowire detectors and LEDs and nanowire solar cells applications.
The light-induced reversible and cyclic reconfiguration of constitutional dynamic networks, consisting of supramolecular nucleic acid structures as constituents and a photoisomerizable trans/cis-azobenzene-functionalized nucleic acid as the trigger is demonstrated. In addition, the cyclic photochemical reconfiguration of the constitutional dynamic networks guides the switchable on/off operation of an emerging hemin/G-quadruplex DNAzyme.
III–V semiconductor
multi-quantum-well nanowires (MQW NWs) via selective-area
epitaxy (SAE) is of great importance
for the development of nanoscale light-emitting devices for applications
such as optical communication, silicon photonics, and quantum computing.
To achieve highly efficient light-emitting devices, not only the high-quality
materials but also a deep understanding of their growth mechanisms
and material properties (structural, optical, and electrical) are
extremely critical. In particular, the three-dimensional growth mechanism
of MQWs embedded in a NW structure by SAE is expected to be different
from that of those grown in a planar structure or with a catalyst
and has not yet been thoroughly investigated. In this work, we reveal
a distinctive radial growth evolution of InGaAs/InP MQW NWs grown
by the SAE metal organic vapor-phase epitaxy (MOVPE) technique. We
observe the formation of zinc blende (ZB) QW discs induced by the
axial InGaAs QW growth on the wurtzite (WZ) base-InP NW and propose
it as the key factor driving the overall structure of radial growth.
The role of the ZB-to-WZ change in the driving of the overall growth
evolution is supported by a growth formalism, taking into account
the formation-energy difference between different facets. Despite
a polytypic crystal structure with mixed ZB and WZ phases across the
MQW region, the NWs exhibit high uniformity and desirable QW spatial
layout with bright room-temperature photoluminescence at an optical
communication wavelength of ∼1.3 μm, which is promising
for the future development of high-efficiency light-emitting devices.
Multifunctional N6-methyladenosine (m6A) has been revealed to be an important epigenetic component in various physiological and pathological processes, but its role in female ovarian aging remains unclear. Thus, we demonstrated m6A demethylase FTO downregulation and the ensuing increased m6A in granulosa cells (GCs) of human aged ovaries, while FTO-knockdown GCs showed faster aging-related phenotypes mediated. Using the m6A-RNA-sequence technique (m6A-seq), increased m6A was found in the FOS-mRNA-3′UTR, which is suggested to be an erasing target of FTO that slows the degradation of FOS-mRNA to upregulate FOS expression in GCs, eventually resulting in GC-mediated ovarian aging. FTO acts as a senescence-retarding protein via m6A, and FOS knockdown significantly alleviates the aging of FTO-knockdown GCs. Altogether, the abovementioned results indicate that FTO in GCs retards FOS-dependent ovarian aging, which is a potential diagnostic and therapeutic target against ovarian aging and age-related reproductive diseases.
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