Seminarium Fizyki Ciała Stałego

Wide bandgap semiconductors are essential for the fabrication of visible light emitters,including both Light Emitting Diodes (LEDs) and Laser Diodes (LDs). The familyof materials that have enabled visible semiconductor optoelectronics comprisescompounds based on three binary materials: AlN, GaN, and InN. Only 30 years ago, widebandgap materials were considered to belong to a specific grey zone between true semiconductors (such as GaAs and Si) and insulators like diamond or NaCl. This categorization was not without reason, as wide bandgap materials are challenging in terms of growth, doping, and surface properties, including the fabrication of metal contacts. Additionally, for AlInGaN semiconductors crystallizing in the wurtzite structure, there is the issue of large internal dielectric polarization. However, as we know, most of these problems have been resolved over the past two decades, enabling the formation of a vast visible and UV light optoelectronics industry. In this presentation, I would like to focus on the remaining challenges posed by nature and use the example of semiconductor laser diodes to illustrate this ongoing battle.