scholarly journals Low-energy room-temperature optical switching in mixed-dimensionality nanoscale perovskite heterojunctions

2021 ◽  
Vol 7 (18) ◽  
pp. eabf1959
Author(s):  
Ji Hao ◽  
Young-Hoon Kim ◽  
Severin N. Habisreutinger ◽  
Steven P. Harvey ◽  
Elisa M. Miller ◽  
...  

Long-lived photon-stimulated conductance changes in solid-state materials can enable optical memory and brain-inspired neuromorphic information processing. It remains challenging to realize optical switching with low-energy consumption, and new mechanisms and design principles giving rise to persistent photoconductivity (PPC) can help overcome an important technological hurdle. Here, we demonstrate versatile heterojunctions between metal-halide perovskite nanocrystals and semiconducting single-walled carbon nanotubes that enable room-temperature, long-lived (thousands of seconds), writable, and erasable PPC. Optical switching and basic neuromorphic functions can be stimulated at low operating voltages with femto- to pico-joule energies per spiking event, and detailed analysis demonstrates that PPC in this nanoscale interface arises from field-assisted control of ion migration within the nanocrystal array. Contactless optical measurements also suggest these systems as potential candidates for photonic synapses that are stimulated and read in the optical domain. The tunability of PPC shown here holds promise for neuromorphic computing and other technologies that use optical memory.

1993 ◽  
Vol 300 ◽  
Author(s):  
E. Wendler ◽  
T. Bachmann ◽  
W. Wesch

ABSTRACTIon implantation induced damage production in GaAs and InP is investigated using Rutherford backscattering spectrometry in combination with channeling techniques and near-edge optical measurements. 200 keV and 1.6 MeV Ar+ ions are implanted at room temperature in GaAs and InP with ion doses varying between 2 × 1012 cm−2 and 3 × 1015 cm−2. Our results show that InP behaves similar for the two implantation energies and no influence of energy loss in electronic processes is found. In GaAs in the region of maximum nuclear energy deposition almost no difference in the damage production occurs for the two implantation energies. But for 1.6 MeV Ar+ implantation within the first 500 nm the defect concentration is very low in comparison to the nuclear energy deposition, which may be the consequence of ionizationinduced defect annealing and/or of the fact that in this depth region the amount of nuclear energy deposition is less than a critical value being necessary for the production of heavily damaged and amorphous zones.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3161
Author(s):  
Sandra Zarska ◽  
Damian Kulawik ◽  
Volodymyr Pavlyuk ◽  
Piotr Tomasik ◽  
Alicja Bachmatiuk ◽  
...  

The bromination of multi-walled carbon nanotubes (MWCNT) was performed with vapor bromine in a closed vessel, and they were subjected to intensive stirring with a magnetic stirrer for up to 14 days. The efficiency of bromination was compared depending upon duration. The structure and surface of the crude and purified products were characterized by detailed physicochemical analyses, such as SEM/EDS, TEM, XRD, TGA, Raman, and XPS spectroscopies. The studies confirmed the presence of bromine covalently bound with nanotubes as well as the formation of inclusion MWCNT–Br2 complexes. It was confirmed that Br2 molecules are absorbed on the surface of nanotubes (forming the CNT-Br2 complex), while they can dissociate close to dangling bonds at CNT defect sites with the formation of covalent C−Br bonds. Thus, any covalent attachment of bromine to the graphitic surface achieved around room temperature is likely related to the defects in the MWCNTs. The best results, i.e., the highest amount of attached Br2, were obtained for brominated nanotubes brominated for 10 days, with the content of covalently bound bromine being 0.68 at% (by XPS).


RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13183-13192
Author(s):  
Jacqueline M. Cole ◽  
David J. Gosztola ◽  
Sven O. Sylvester

Single crystals that behave as optical switches are desirable for a wide range of applications, from optical sensors to read–write memory media.


Author(s):  
Maged Abdelsamie ◽  
Tianyang Li ◽  
Finn Babbe ◽  
Junwei Xu ◽  
Qiwei Han ◽  
...  

2021 ◽  
Vol 7 (21) ◽  
pp. eabf8049
Author(s):  
Rui Su ◽  
Sanjib Ghosh ◽  
Timothy C. H. Liew ◽  
Qihua Xiong

Strong light-matter interaction enriches topological photonics by dressing light with matter, which provides the possibility to realize active nonlinear topological devices with immunity to defects. Topological exciton polaritons—half-light, half-matter quasiparticles with giant optical nonlinearity—represent a unique platform for active topological photonics. Previous demonstrations of exciton polariton topological insulators demand cryogenic temperatures, and their topological properties are usually fixed. Here, we experimentally demonstrate a room temperature exciton polariton topological insulator in a perovskite zigzag lattice. Polarization serves as a degree of freedom to switch between distinct topological phases, and the topologically nontrivial polariton edge states persist in the presence of onsite energy perturbations, showing strong immunity to disorder. We further demonstrate exciton polariton condensation into the topological edge states under optical pumping. These results provide an ideal platform for realizing active topological polaritonic devices working at ambient conditions, which can find important applications in topological lasers, optical modulation, and switching.


2007 ◽  
Vol 994 ◽  
Author(s):  
Satoru Suzuki ◽  
Yoshihiro Kobayashi

AbstractWe show that low-energy (20 eV–20 keV) electron or photon irradiation extinguishes the characteristic physical and chemical properties of single-walled carbon nanotubes, indicating that the irradiation damages the nanotubes. The irradiation-induced defects convert the electric properties of metallic SWNTs to semiconducting, and the nominal bandgap can be tuned simply by the irradiation dose. The defects also have the following interesting properties. The damage and recovery are reversible, indicating that the number of carbon atoms is preserved. The damage and recovery strongly depend on the diameter, suggesting that the damage is prominent in a rolled up graphene sheet, but not in a planar one. The activation energy of the defect healing is so small, depending on the diameter, that the defects can be healed even at room temperature or below.


2014 ◽  
Vol 53 (42) ◽  
pp. 11242-11247 ◽  
Author(s):  
Heng-Yun Ye ◽  
Yi Zhang ◽  
Da-Wei Fu ◽  
Ren-Gen Xiong

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