Structural and opto-electrical investigation of InGaN/GaN nanoLED arrays

In recent years, gallium nitride-based LEDs have been continuously developed and employed in not only solid state lighting but also for bio-imaging and optical sensor applications. By integrating them with CMOS control electronics, matrix-addressed GaN microLED arrays could be utilized as a new microscope technique in life sciences. Although those optoelectronic devices exhibit promising results, their spatial resolution is still low, which results from the LED dimensions with pixel and pitch sizes in the range of several tens of micrometers. In this work, InGaN/GaN nanoLED arrays were designed and fabricated to be used as a nanoillumination source inside an on-chip microscope. As the LED pixel dimensions are scaled down to the sub-micron range, the relationship between the nanoscale size and performance of a LED is of interest. Opto-electrical measurements of nanoLEDs were conducted with nanoneedle probing tips inside an SEM. Hence, I-V and electroluminescence characteristics of light sources with dimensions of smaller than one micrometer could be extracted. Technological details of the challenging processing of these structures will also be presented.