Development of chipscale InGaN RGB displays using strain-relaxed nanosphere-defined nanopillars

• Published in: Nanotechnology Vol. 33; no. 28; pp. 285202 - 285211
• Main Authors: Fu, Wai Yuen, Choi, Hoi Wai
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 22.04.2022
• Subjects: chipscale; displays; InGaN; RGB; InGaN; RGB; displays; chipscale
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/ac6399

Chip-scale red, green and blue (RGB) light emission on an InGaN/GaN multi-quantum well wafer adopting a top-down fabrication approach is demonstrated in this study, facilitated by shadow-masked nanosphere lithography for precise site-controlled nano-patterning. Exploiting the strain relaxation mechanism by fabricating arrays of nanosphere-defined nanopillars of two different dimensions utilizing a sequential shadow-masked nanosphere coating approach into the blue and green light-emitting pixel regions on a red-light emitting InGaN/GaN wafer, RGB light emission from a monolithic chip is demonstrated. The micro-sized RGB light-emitting pixels emit at 645 nm-680 nm, 510 nm-521 nm and 475 nm-498 nm respectively, achieving a maximum color gamut of 60% NTSC and 72% sRGB. Dimensional fluctuations of the nanopillars of 73% and 71% for the green and blue light-emitting pixels, respectively, are estimated from scanning electron microscope images of the fabricated device, corresponding to fluctuations in spectral blue-shifts of 5.4 nm and 21.2 nm as estimated by strain-coupled · Schrödinger calculations, consistent with observations from micro-photoluminescence ( -PL) mapping which shows deviations of emission wavelengths for the RGB light-emitting pixels to be 8.9 nm, 14.9 nm and 23.7 nm, respectively. The RGB pixels are also configured in a matrix-addressable configuration to form an RGB microdisplay, demonstrating the feasibility of the approach towards chip-scale color displays.