Using one material system from the near infrared into the ultraviolet is an attractive goal, and may be achieved with (In,Al,Ga)N. This III-N material system, famous for enabling blue and white solid-state lighting, has been pushing towards longer wavelengths in more recent years. With a bandgap of about 0.7 eV, InN can emit light in the near infrared, potentially overlapping with the part of the electromagnetic spectrum currently dominated by III-As and III-P technology. As has been the case in these other III–V material systems, nanostructures such as quantum dots and quantum dashes provide additional benefits towards optoelectronic devices. In the case of InN, these nanostructures have been in the development stage for some time, with more recent developments allowing for InN quantum dots and dashes to be incorporated into larger device structures. This review will detail the current state of metalorganic chemical vapor deposition of InN nanostructures, focusing on how precursor choices, crystallographic orientation, and other growth parameters affect the deposition. The optical properties of InN nanostructures will also be assessed, with an eye towards the fabrication of optoelectronic devices such as light-emitting diodes, laser diodes, and photodetectors.

Integration of nitrides with other material systems has recently become of interest due to the high performance of GaN-based high-electron mobility transistors. However, the elevated growth temperatures often used to grow high quality AlN pose challenges toward metalorganic chemical vapor deposition (MOCVD) on temperature sensitive substrates such as processed wafers. In this work, the growth of AlN was conducted at temperatures below 550 °C via MOCVD using a flow-modulated epitaxy scheme, and their morphological, compositional, and electronic properties of these films were investigated. Sheet charges up to 2.1 × 10¹³ cm⁻² and mobilities on the order of 400 cm²/V s were measured for two dimensional electron gases, which formed at the interface between the low temperature grown AlN layers and the semi-insulating GaN base layers deposited at high temperatures. Despite their low growth temperatures, nominally pure AlN barrier layers exhibited measurable unintentional gallium incorporation adjacent to the GaN interface. The result sets the stage for the integration of nitride-based electronics via epitaxy-based schemes on temperature sensitive substrates.

Heterogeneous integration of materials systems for devices and circuits is becoming of increasing interest, particularly for the wide bandgap nitrides in both optoelectronic and electronic applications. However, typical high growth temperatures of GaN by metalorganic vapor phase epitaxy prevent the growth of GaN on wafers with temperature sensitive materials. This work presents a flow modulation epitaxy (FME) growth scheme which allows for step-flow growth of GaN at temperatures below 600 °C. The utilization of a pulsed growth scheme such as FME allows for the mitigation of challenges associated with limited motion of adatoms at lower growth temperatures. Factors such as temperature, precursor flow rate, cycle time, and film thickness were explored. Under optimized conditions, step-flow growth of GaN films at 550 °C was demonstrated. In addition to an improved surface morphology over layers grown in the conventional continuous growth mode, the carbon and oxygen residual impurity concentrations in the FME grown layers were significantly lower, with carbon and oxygen contents of 9 × 10 ¹⁷ cm ⁻³ and 8 × 10 ¹⁶ cm ⁻³ , respectively. Although the growth rate of the low temperature growth was very slow, ∼ 0.006 Å/s, the flow modulation growth scheme developed here provides a pathway towards further integration of GaN with temperature sensitive materials.

Marine energy is poised to become an important renewable energy contributor for the U.S., but widespread deployment of the technology hinges on its benefits outweighing the potential ecological impacts. One stressor marine energy installations introduce is light, which is known to cause varying responses among wildlife and has not yet been addressed as an environmental concern. This review discusses requirements and regulations for similar structures and how lighting design choices can be made to meet these requirements while minimizing environmental consequences. More practical guidance on implementing lighting for marine energy is needed, as well as updated guidelines to reflect technological and research advances. Known responses of wildlife to light are introduced in addition to how the responses of individuals may lead to ecosystem-level changes. The impact of light associated with marine energy installations can be reduced by following basic guidance provided herein, such as removing excess lighting, using lights with high directionality, and employing controls to reduce light levels. Continued research on animal responses to light, such as findings on minimum light levels for animal responses, alongside the development of highly-sensitivity spectral characterization capabilities can further inform lighting guidelines for deploying future open ocean marine energy devices.

The heterogeneous integration of III-nitride materials with other semiconductor systems for electronic devices is attractive because it combines the excellent electrical properties of the III-nitrides with other device platforms. Pursuing integration through metalorganic chemical vapor deposition (MOCVD) is desirable because of the scalability of the technique, but the high temperatures required for the MOCVD growth of III-nitrides (>1000 °C) are incompatible with direct heteroepitaxy on some semiconductor systems and fabricated wafers. Thus, the MOCVD growth temperature of III-nitride films must be lowered to combine them with other systems. In this work, 16 nm-thick Si:GaN films were grown by MOCVD at 550 °C using a flow modulation epitaxy scheme. By optimizing the disilane flow conditions, electron concentrations up to 5.9 × 10¹⁹ cm⁻³ were achieved, resulting in sheet resistances as low as 1070 Ω/□. Film mobilities ranged from 34 to 119 cm² V⁻¹ s⁻¹. These results are promising for III-nitride integration and expand device design and process options for III-nitride-based electronic devices.