Surface/Interface Engineering for Constructing Advanced Nanostructured Light-Emitting Diodes with Improved Performance: A Brief Review

Abstract

With the rise of nanoscience and nanotechnologies, especially the continuous deepening of research on low-dimensional materials and structures, various kinds of light-emitting devices based on nanometer-structured materials are gradually becoming the natural candidates for the next generation of advanced optoelectronic devices with improved performance through engineering their interface/surface properties. As dimensions of light-emitting devices are scaled down to the nanoscale, the plentitude of their surface/interface properties is one of the key factors for their dominating device performance. In this paper, firstly, the generation, classification, and influence of surface/interface states on nanometer optical devices will be given theoretically. Secondly, the relationship between the surface/interface properties and light-emitting diode device performance will be investigated, and the related physical mechanisms will be revealed by introducing classic examples. Especially, how to improve the performance of light-emitting diodes by using factors such as the surface/interface purification, quantum dots (QDs)-emitting layer, surface ligands, optimization of device architecture, and so on will be summarized. Finally, we explore the main influencing actors of research breakthroughs related to the surface/interface properties on the current and future applications for nanostructured light-emitting devices.

Surface/Interface Engineering for Constructing Advanced Nanostructured Photodetectors with Improved Performance: A Brief Review

“…Much research on semiconductor surfaces caused by cleaving in ultrahigh vacuum suggested that the formation of surface states is attributed to dangling bonds at the surface [49]. According to a previous report [47], the schematic diagram of the surface level is shown in Figure 1. The surface states could also be divided into donor states or acceptor states based on the behavior of the electrons.…”

“…A surface could be defined as atomic layers that do not have three-dimensional continuous environment of bulk materials, three-dimensional continuous environment, or the periodicity of the infinite lattice that is destroyed by the existence of nanostructured surface. For crystal structures, in the direction of the vertical surface, the potential energy of lattice atoms could not have corresponding symmetry, and some new eigenvalues could be obtained in the Hamiltonian characteristic value when the Schrodinger equation is applied through the theory of quantum mechanics [47]. A new energy level could appear and be defined as a surface state, as shown in Figure 1.…”

Van der Waals heterostructures with one-dimensional atomic crystals

“…[265] Suffering from the defects and surface states, which usually lead to the non-radiative recombination in 1D atomic crystals, the device only shows a broad sub-bandgap electroluminescence (EL) emission centered at 380 nm. To minimize the influence of surface/interface states and improve efficiencies, stabilities, and lifetime of devices, various strategies have been explored, including shell layer shielding [266], interfacial structure optimization [267][268][269], surface functionalization [270], etc. You et al reported a feasible method of directly bonding active n-ZnO nanowires array onto AlN-coated p-GaN wafer [271].…”

Editorial of Special Issue “Nanostructured Light-Emitters”

“…Study on β-Ga 2 O 3 and its function as the substrate for vertical structure LEDs have been intensively investigated. Some of the key advantages of β-Ga 2 O 3 are high n-type conductivity, low lattice mismatch with III-nitrides, and high transparency (>80%) in blue and UV region, enabling β-Ga 2 O 3 as a highly potential substrates for high-performance light-emitters.In another review paper, Zhou et al [2] summarized recent studies on the interface/surface properties of low-dimensional materials and structures. Importantly, the performance of nanostructured LEDs can be significantly improved by engineering their surface/interface characteristics with a focus on the surface/interface purification, quantum dots-emitting layer, surface ligands, and optimization of device architecture.The recent progress made in AlGaN nanowires for UV LEDs is reported in the third review paper, entitled "AlGaN nanowires for UV LEDs: Recent progress, challenges, and prospects" [3].…”

“…In another review paper, Zhou et al [2] summarized recent studies on the interface/surface properties of low-dimensional materials and structures. Importantly, the performance of nanostructured LEDs can be significantly improved by engineering their surface/interface characteristics with a focus on the surface/interface purification, quantum dots-emitting layer, surface ligands, and optimization of device architecture.…”