Beyond solid-state lighting: Miniaturization, hybrid integration, and applications og GaN nano- and micro-LEDs

Gallium Nitride (GaN) light-emitting-diode (LED) technology has been the revolution in modern lighting. In the last decade, a huge global market of efficient, long-lasting and ubiquitous white light sources has developed around the inception of the Nobel-price-winning blue GaN LEDs. Today GaN optoelectronics is developing beyond lighting, leading to new and innovative devices, e.g. for micro-displays, being the core technology for future augmented reality and visualization, as well as point light sources for optical excitation in communications, imaging, and sensing. This explosion of applications is driven by two main directions: the ability to produce very small GaN LEDs (microLEDs and nanoLEDs) with high efficiency and across large areas, in combination with the possibility to merge optoelectronic-grade GaN microLEDs with silicon microelectronics in a fully hybrid approach. GaN LED technology today is even spreading into the realm of display technology, which has been occupied by organic LED (OLED) and liquid crystal display (LCD) for decades. In this review, the technological transition towards GaN micro- and nanodevices beyond lighting is discussed including an up-to-date overview on the state of the art

Carbon Nanotubes

Since their discovery in 1991, carbon nanotubes have been considered as one of the most promising materials for a wide range of applications, in virtue of their outstanding properties. During the last two decades, both single-walled and multi-walled CNTs probably represented the hottest research topic concerning materials science, equally from a fundamental and from an applicative point of view. There is a prevailing opinion among the research community that CNTs are now ready for application in everyday world. This book provides an (obviously not exhaustive) overview on some of the amazing possible applications of CNT-based materials in the near future

Metal oxide nanostructures: synthesis, characterization, optical properties and their applications as gas sensors

Research on nanostructurred metal oxides (MOXs) represents a fertile path for the potentiality these materials have in several application. Particularly interesting is the gas sensing field, often based on the use of semiconductor nature of MOX and their intrinsic structural properties, such as crystallinity and presence of defect states, that make them appealing research material both for improving existing devices and for novel applicative systems. In this direction is setting forth the study of nanostructured MOX properties for the development of optochemical gas sensors, field in which my Ph.D. work is contextualized. My research project consisted in the morphological, structural and optical characterization of nanostructured MOX (TiO2 and ZnO) thin films in view of application in optical gas sensing. Material ablation and deposition is obtained by pulsed laser ablation (PLD) technique in the nanosecond and femtosecond pulse regime wicth characterization performed by means of scanning electron microscopy (SEM), X-ray diffractometry (XRD), continuous wave (CWPL) and time resolved (TRPL) photoluminescence, excitation photoluminescence (PLE) and absorption spectrophotometry (visible region and IR). Optical responses (luminescence) of materials are studied varying conditions of the ambient gas environment in interaction with them: By comparison of materials different stimulus and gas species responses, we will quantitatively screen out pros and cons of nanostructured metal oxide applications as optical sensors

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry was held on 1–15 July 2021. The scope of this online conference was to gather experts that are well-known worldwide who are currently working in chemical sensor technologies and to provide an online forum for the presention and discussion of new results. Throughout this event, topics of interest included, but were not limited to, the following: electrochemical devices and sensors; optical chemical sensors; mass-sensitive sensors; materials for chemical sensing; nano- and micro-technologies for sensing; chemical assays and validation; chemical sensor applications; analytical methods; gas sensors and apparatuses; electronic noses; electronic tongues; microfluidic devices; lab-on-a-chip; single-molecule sensing; nanosensors; and medico-diagnostic testing

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.Peer ReviewedPostprint (published version

An unconventional type of measurement with chemoresistive gas sensors exploiting a versatile measurement system

To characterize chemoresistive sensors based on novel materials a versatile measurement system is required that is able to accurately control/measure all the quantities of interest (among which test gas mixture composition, relative humidity, sensor surface temperature, sensor resistance). In the last years the authors have developed a laboratory measurement system with these characteristics [1], which can be used with chemoresistive sensors provided with both a heater and a temperature sensor. In this contribution an unconventional measurement technique made it possible by the above system, improved to be used also with sensors not provided with a dedicated temperature sensor, will be presented. The technique consists in driving the heater, on the basis of the sensing film temperature, in order to maintain constant the sensing film resistance while varying the test gas mixture composition