Visible White‐Light Emission and Carrier Dynamics Observed in Full‐Series GaSe_1‐xS_x (0≤x≤1) Multilayers

Abstract

Near‐band‐edge emissions ranging from red (≈630 to 602 nm) to green (≈550 to 534 nm) and blue (≈494 to 480 nm) colors have been detected in full‐series GaSe1‐xSx (0≤x≤1) multilayers using micro‐photoluminescence (µPL) measurements from 4 to 300 K. The multilayered chalcogenides crystallize in a hexagonal structure, with observed mixed stacking phases of ε and β polymorphs through X‐ray diffraction and Raman measurements. The µPL results, along with experimental band‐edge characterization through thermoreflectance, identify the ε‐stacked phase as the crucial phase responsible for direct recombination and the emission of free excitons within the visible range. A mixed‐color white light is created by PL, which is emitted from the layered GaSe1‐xSx series of different colors, and is positioned at the center of the CIE coordination plot (i.e., white color). To assess the emission properties of both band edges and defects in the layered compounds, time‐resolved photoluminescence (TRPL) is employed, using an area mapping function. The photoluminescence decay lifetime increases as the sulfur content is increased, owing to the greater occurrence of mixed‐phase stacking faults near the β‐GaS end within the GaSe1‐xSx (0≤x≤1) series. The multilayer GaSe1‐xSx (0≤x≤1) represents a distinct 2D chalcogenide series well‐suited for emitting full‐color visible light.

Phosphorus-Doped Multilayer In6Se7: The Study of Structural, Electrical, and Optical Properties for Junction Device

“…III–VI layered semiconductors have gained significant attention due to their unique electronic and optical properties as well as specific technological applications. , The III and VI monochalcogenides possess a general chemical formula of MX, where M is a group III element (such as Ga or In), and X is a chalcogen atom (such as Te, Se, or S). − One of the most exciting properties of III–VI layered semiconductors is their direct band edge constructed in the multilayer form, − this can make them an ideal candidate for various optoelectronics applications such as solar cells, photodetectors, and light-emitting diodes. − Indium is easily oxidized and exhibits intriguing characteristics within the group III elements, especially as it forms many compounds by synthesis with group VI elements, such as In–O, , In–S, − In–Se, − and In–Te. , The formation of In–Se bonding is important in III–VI compounds, and it has been extensively studied and investigated for its derivatives in various applications. ,,− The investigation of In–Se-based materials is driven by their potential utilization in various applications, including solar cells, , Li-ion batteries, − and ionizing radiation detectors, due to their noteworthy physical features, such as optical and electrical properties . The materials of the In–Se system have also attracted considerable interest due to its intrinsic structural properties, including phase transition (transformation), multicrystalline zones consisting different phases, and structural imperfections. , Extensive research has been conducted on materials derived from the In–Se system, − and numerous works have investigated the phase diagram of the In–Se system with different stoichiometry and different modifications. − Previous investigations have reported that the presence of stable phases in this In–Se system includes the stoichiometric compositions of InSe, In 2 Se 3 , In 4 Se 3 ,…”