CMOS/GaN integration in micro/nanoLED arrays for biomedical applications
[eng] Since their inception, LEDs have replaced traditional incandescent and fluorescent lighting in numerous sectors, ranging from general illumination and display technologies to specialized applications, such as in the biomedical field. LEDs provide significant energy savings, reduced environment...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/218519 |
| Acceso en línea: | https://hdl.handle.net/2445/218519 http://hdl.handle.net/10803/693573 |
| Access Level: | acceso abierto |
| Palabra clave: | Microscòpia Semiconductors Díodes electroluminescents Microscopy Light emitting diodes |
| Sumario: | [eng] Since their inception, LEDs have replaced traditional incandescent and fluorescent lighting in numerous sectors, ranging from general illumination and display technologies to specialized applications, such as in the biomedical field. LEDs provide significant energy savings, reduced environmental impact, and greater design flexibility, marking a significant shift in how light is utilized across different domains, even being able to substitute lasers in a wide range of applications. Building on the success of conventional LEDs, microLED technology has emerged as a groundbreaking advancement. MicroLEDs are significantly smaller than traditional LEDs, typically ranging from a few micrometers to a few hundred micrometers in size. This miniaturization opens new possibilities for high-resolution displays, where microLEDs offer superior brightness, contrast, and energy efficiency compared to OLED and LCD technologies. Additionally, the fast response times and robustness of microLEDs make them suitable for dynamic and demanding applications, such as augmented reality and virtual reality displays, as well as advanced biomedical devices. The integration of CMOS technology with GaN microLEDs in the development of products based on micro or nanoLED arrays is a significant step forward for all the applications where microLEDs can be used. In this work, we will focus on their potential usage in the biomedical field. CMOS technology is known for its scalability, low power consumption and high integration density, which are essential characteristics for creating compact and efficient electronic systems. On the other hand, GaN is valued for its high electron mobility, thermal stability and direct wide bandgap properties, enabling efficient light emission and operation under high power conditions. Combining these technologies, it is possible to create lighting devices with micro or nanoLEDs that leverage the best attributes of both materials, resulting in a compact device with enhanced performance and functionality. This PhD thesis explores the development of CMOS drivers to be integrated with GaN microLED arrays, addressing the inherent challenges posed by the material and processing incompatibilities between silicon-based CMOS and GaN. This research provides a detailed analysis of the optical, electrical, and thermal performance of these devices, demonstrating their superior characteristics compared to conventional LED arrays and other light sources. In the context of biomedical applications, the thesis focuses on microscopy and PoC diagnostics. In advanced microscopy, integrated micro/nano LED arrays can provide high-intensity, uniform illumination with precise control over wavelength and intensity. This capability enhances imaging resolution and contrast, allowing for more detailed and accurate observations at the cellular and molecular levels. The miniaturized form factor of these LEDs also facilitates the development of compact and portable microscopy devices, broadening their accessibility and utility in various medical and research settings. Furthermore, in this thesis we explore the use of micro and nanoLED devices combined with CMOS electronics to create a new type of microscopy technique, Nano-Illumination Microscopy (NIM). For PoC diagnostics, the high speed and high optical power that microLEDs can deliver when driven by CMOS IC is crucial to develop fluorescence based PoC. These arrays can be used to develop portable diagnostic devices that offer real-time monitoring and rapid analysis of biological markers. This is crucial for early disease detection and personalized medicine, where timely and accurate diagnostics can significantly improve patient outcomes. The integration of these LEDs into PoC devices ensures that they are not only effective but also energy-efficient and cost-effective, making them suitable for widespread use, including in resource-limited settings. Furthermore, microLED arrays are a perfect fit to accomplish the ASSURED criteria provided by WHO for PoC devices. In conclusion, this PhD thesis shows that the integration of CMOS and GaN technologies in micro/nano LED arrays offers a transformative approach for advancing biomedical applications, specifically in microscopy and PoC diagnostics. The enhanced performance, combined with the reliability and scalability of these integrated systems, holds significant promise for future innovations in medical diagnostics, treatment, and research. This work lays the groundwork for further exploration and development in the field, potentially leading to new breakthroughs in biomedical technology. |
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