In recent years, low-dimensional (zero-, one-, and two-dimensional) nanostructures have attracted wide attention and become a focus of scientific research and engineering application. This is due to their novel physical and chemical properties caused by size and quantum effects, as well as potential applications in various kinds of devices, for example, optoelectronics, nanoelectronics, and so forth. This special issue is intended to bring the most recent advances in the field of low-dimensional nanostructures for optoelectronic applications. As expected, the research articles in this special issue cover a wide range of topics in this research field, ranging from theoretical simulation to material synthesis, to material characterization, to device fabrication, and to device characterization.
In the paper “The formation site of noninterfacial misfit dislocations in InAs/GaAs quantum dots,” S. Zhou et al. simulate the preferential formation site of noninterfacial 60° mixed dislocations in InAs/GaAs quantum dots and find that the positions near the right edge of the quantum dot are the energetically favourable areas for these dislocations. In the paper “Thickness-dependent strain effect on the deformation of the graphene-encapsulated Au nanoparticles,” S. Ye et al. simulate the effect of strain on the morphology of graphene-encapsulated Au nanoparticles. The modelling results indicate that strain and deformation can be designed by the graphene layer thickness, providing an opportunity to engineer the structure and morphology of the graphene-encapsulated nanoparticles. In the paper “Strain distribution of Au and Ag nanoparticles embedded in Al2O3 thin film,” H. Huang et al. calculate the strain distribution in Au and Ag nanoparticles embedded in amorphous Al2O3 matrix. The calculation results indicate that both the Au and Ag nanoparticles incur compressive strain caused by the Al2O3 matrix. However, the compressive strain existing on the Au nanoparticle is much weaker than that on the Ag nanoparticle. This different strain distribution of Au and Ag nanoparticles in the same host matrix may have a significant influence on the technological potential applications of the Au-Ag alloy nanoparticles.
In the paper “Second-order nonlinearity assisted by dual surface plasmon resonance modes in perforated gold film,” R. Zhou et al. report the enhanced light transmission (assisted with surface plasmon) through a nanoscale square lattice perforated gold film. In the paper “Effects of polaron and quantum confinement on the nonlinear optical properties in a GaAs/As quantum well wire,” L. C. Sugirtham et al. calculate the binding energy of a polaron confined in a GaAs/As quantum well wire with the variational technique and Lee-Low Pines approach and study the effect of polaron and quantum confinement on the nonlinear optical properties of GaAs/As quantum well wire. In the paper “Nonnegative matrix factorization numerical method for integrated photonic cavity based spectroscopy,” Z. Huang et al. use a nonnegative matrix factorization method to improve the spectral resolution of integrated photonic cavity based spectroscopy. The spectral resolution can be improved from 5.5 to 1.8 nm, which is helpful for enhancing the spectral resolution of miniature spectrometers.
In the paper “Void structures in regularly patterned ZnO nanorods grown with the hydrothermal method,” Y.-F. Yao et al. study the effect of thermal annealing on the void structures and optical properties of ZnO nanorod arrays obtained by hydrothermal method, which provides good understanding about the structural change of ZnO nanorods under thermal annealing. In the paper “Hydrothermal synthesis and mechanism of unusual zigzag Ag2Te and Ag2Te/C core-shell nanostructures,” S. Manzoor et al. fabricate the zigzag silver telluride nanowires and silver telluride coated with carbon core-shell nanowires via simple hydrothermal route, which has promising applications in optoelectronic devices. In the paper “Preparation and characterization of graphene oxide,” J. Song et al. report the fabrication of graphene oxide films with the modified Hummer method, which presents a promising way to synthesize graphene oxide films on a large scale. In the paper “Mixed phases at the bottom interface of Si-doped AlGaN epilayers of optoelectronic devices,” C.-h. Yu et al. present a study of the crystalline structures of Si-doped Al0.4Ga0.6N layers grown on unintentionally doped AlGaN buffer layer with an AlN nucleation layer, which is helpful for understanding the fundamental properties of high aluminium content Si-doped AlGaN alloys and providing specific guidance on the fabrication of multilayer optoelectronic devices where weak cubic subgrains potentially occur and exert complicated influence on device performance.
In the paper “Improving light outcoupling efficiency for OLEDs with microlens array fabricated on transparent substrate,” J. Wang et al. utilize microlens array substrate to increase the light output efficiency of organic LED, which is very encouraging. In the paper “A flexible blue light-emitting diode based on ZnO nanowire/polyaniline heterojunctions,” Y. Y. Liu et al. report an organic/inorganic light-emitting diode consisting of n-type vertically aligned ZnO nanowires and p-type proton acid doped polyaniline. A broad blue light emission band ranging from 390 to 450 nm is observed for the device, and the turn-on voltage of the device is ~3.5 V. In combination with easy fabrication, flexibility, low power consumption, and mechanical robustness, this novel device is very promising for the application of blue light-emitting diodes. In the paper “Crystallites of -sexithiophene in bilayer small molecule organic solar cells double efficiency,” M. Radziwon et al. present an interesting study on the -6T/C60 inverted bilayer organic solar cells by investigating the influence of -sexithiophene (-6T) nanostructures on the performance parameters. It is found that the crystalline nanostructures can significantly improve the device conversion efficiency.
In summary, as reflected by its content this special issue provides a broad panorama for research in this specific field and will benefit the readers, especially those working in this field.
Acknowledgments
We would like to thank our reviewers for their time and comments and thank the authors for their contributions to this special issue. This special issue could not have been successful without their contribution and support.
Wen Lei
Lorenzo Faraone
H. Hoe Tan
Wei Lu