Assessment of Occupational Exposure to Indium Dust for Indium-Tin-Oxide Manufacturing Workers

According to recent research, indium nanoparticles (NPs) are more toxic than micro-sized particles. While cases of indium lung disease have been reported worldwide, very little research has been conducted on the occupational exposure to indium NPs. Recently, an indium-related lung disease was reported in Korea, a global powerhouse for display manufacturing. In this study, we conducted an assessment ofoccupational exposure at an indium tin oxide (ITO) powder manufacturing plant, where the first case of indium lung disease in Korea occurred. Airborne dustwas obtained from a worker’s breathing zone, and area sampling in the workplace environment was conducted using real-time monitoring devices. Personal samples were analyzed for the indium concentrations in total dust, respirable dust fraction, and NPs using personal NPs respiratory deposition samplers. The total indium concentration of the personal samples was lower than the threshold limit value recommended by the American Conference of Governmental Industrial Hygienists (ACGIH TLV), which was set as occupational exposure limit (OEL). However, the respirable indium concentration exceeded the recently set ACGIH TLV for the respirable fraction of indium dust. The concentration of indium NPs ranged between 0.003 and 0.010 × 10−2 mg/m3, accounting for only 0.4% of the total and 2.7% of the respirable indium particles. This was attributed to the aggregating of NPs at the µm sub-level. Given the extremely low fraction of indium NPs in the total and respirable dust, the current OEL values, set as the total and respirable indium concentrations, do not holistically represent the occupational exposure to indium NPs or prevent health hazards. Therefore, it is necessary to set separate OEL values for indium NPs. This study covers only the process of handling ITO powder. Therefore, follow-up studies need to be conducted on other ITO sputtering target polishing and milling processes, which typically generate more airborne NPs, to further investigate the effects of indium on workers and facilitate the necessary implementation of indium-reducing technologies.

Увеличение эффективности трехпереходных солнечных элементов за счет метаморфного InGaAs-субэлемента

The efficiency of GaInP/GaAs/InxGa1-xAs triple-junction solar cells obtained by replacing (in the widely used "classical" GaInP / GaAs / Ge heterostructure) the lower germanium with InxGa1-xAs subcell formed using the metamorphic growth technology has been investigated. Based on an original approach, the optimal indium concentration in the narrow-gap subcell has been found. The main parameters of InxGa1-xAs subcells with an indium concentration from x = 0.11 to 0.36 were determined and were used to calculate the IV characteristics of GaInP/GaAs/InxGa1-xAs solar cells. It has been determined that at x=0.28 the efficiency of the triple-junction solar cell increases by 3.4% (abs) in comparison with the “classical” solar cell, reaching a value of 40.3% (AM1.5D). Also it has been shown that the efficiency of such solar cells can be increased up to 41%.

Room Temperature Ferromagnetism in InGaN Nanostructures Induced by Cr+ ion Implantation

This paper presents the magnetic properties of chrome ion (Cr+) implanted InxGa1−xN (x = 0.1, 0.3, 0.5 and 1.0) nanostructures grown by molecular beam epitaxy (MBE). The Cr+ implantation was conducted at 110 keV with three doses, namely 2.6 × 1015, 5.3 × 1015, and 1.3 × 1016 ions/cm2. The as-grown nanostructures exhibited diamagnetism before and after ion implantation without annealing. However, after annealing, the nanostructures exhibited ferromagnetism at room temperature. The saturation magnetization (Ms) and coercive force (Hc) increase with increasing Cr+ dose. The Ms of the InN nanorods with diameters of 100–160 nm is larger than that of those with small diameters of 60–80 nm. For InGaN nanostructures, the indium concentration—that is, the band structure—is more important than the diameters of the nanorods for the same doping level of Cr ions. The Ms of InGaN nanorods with an indium concentration of 10% reaches its maximum. The zero-field cooled (ZFC) and field-cooled (FC) curves show that nanostructures have no parasitic magnetic phases.

Indium concentration fluctuations in InGaN/GaN quantum wells

Secondary ion mass spectrometry measurements can provide specific information on In fluctuations in InGaN quantum wells.