Search

Silver (Ag) nanostructures have demonstrated the feasibility of being utilized in various optoelectronic, catalytic, biomedical, and sensor devices due to their excellent surface plasmon resonance characteristics. The geometrical structure, spacing, and spatial arrangement of nanostructures are crucial for controlling the properties and device performance. Herein, we demonstrate the fabrication of various configurations of self-assembled Ag nanostructures on GaN (0001) by the systematic control of deposition thickness and annealing duration. The surface morphology evolution is thoroughly investigated, and the corresponding influence on optical properties is probed. The evolution of Ag nanostructures in response to thermal annealing is described based on the dewetting of thin films, Volmer–Weber growth model, coalescence growth, and surface energy minimization mechanism. For the deposition amount variation between 1 and 100 nm, the Ag nanostructures show gradual morphological transitions such as small nano...

Porous GaN exhibits unique optoelectronic, chemical, and physical properties such as shift of band gap, increased surface area ratio, excellent chemical, mechanical, and thermal stability as well as efficient luminescence as compared to its bulk counterpart. Herein, we demonstrate a precise, efficient, and still cost-effective method of the fabrication of porous GaN through the enhanced GaN decomposition by using Au nanoparticles (NPs) as a catalyst, in which the size, density, and shape of the pores (nanoholes, NHs) can be precisely controlled. By the thermal annealing assisted with the Au NPs, the NHs are successfully fabricated, and the existence of Au NPs significantly accelerate the GaN decomposition at the interface between the NPs and GaN due to the Ga absorption by the Au NPs. We systematically study the formation mechanism of NHs assisted by the Au NPs by means of annealing temperature, duration, and Au deposition amount, and the results are systematically analyzed and discussed.

We studied the evolution of Au nanostructures in dome-shaped Au droplets that merge into Au nanostructures on Si(111) by systematically controlling the Au deposition amount (DA) under a fixed annea...

We demonstrate a number of unseen self-assembled nanostructure complexes fabricated on various GaAs surface indexes by droplet epitaxy. Even under identical growth conditions, the configuration of nanostructure complexes is distinctive on each surface. The morphology evolution of nanostructure complexes is kinetically and energetically analyzed in determining the correlation between shape of nanostructure complexes and atomic surface matrixes with atomic ball−stick models. By systematically varying growth environment, we report many uncanny nanostructure complexes on given surface indexes.

We report on the ability to fabricate super low density InGaAs semiconductor ring-shaped nanocrystals on a GaAs (100) surface by molecular beam epitaxy. Specifically, we demonstrate densities down to 2.3 × 106 cm−2 with only self-assembled methods based on droplet epitaxy. This is several orders of magnitude lower than conventional nanostructures. The formation of these ring-shaped nanostructures is driven by a self-assembled indium nanodrilling mechanism and diffusion during crystallization.

We demonstrate the formation of hybrid molecules composed of a pair of a metal particle and a semiconductor quantum ring (QR) by using molecular beam epitaxy on a GaAs (100) surface. To form three-dimensional semiconductor InGaAs QRs with a hole in the center of the structure, a thin layer (10 monolayer) of GaAs was applied on InAs quantum dots, which transformed the distribution of surface free energy. These InGaAs QRs were then used as a template for the localization of Ga metal particles; there was one metal particle on a QR. By choosing the optimal surface temperature (most favorable thermal energy), the surface diffusion of Ga adatoms was effectively enhanced. This, in turn, allowed the localization of Ga metal particles on InGaAs QRs, consequently forming hybrid molecules. This study helps understand the formation of various types of hybrid molecules that will be used in applications in optoelectronics.