Micro-LEDs (µLEDs) have been explored for augmented and virtual reality display applications that require extremely high pixels per inch and luminance1,2. However, conventional manufacturing processes based on the lateral assembly of red, green and blue (RGB) µLEDs have limitations in enhancing pixel density3–6. Recent demonstrations of vertical µLED displays have attempted to address this issue by stacking freestanding RGB LED membranes and fabricating top-down7–14, but minimization of the lateral dimensions of stacked µLEDs has been difficult. Here we report full-colour, vertically stacked µLEDs that achieve, to our knowledge, the highest array density (5,100 pixels per inch) and the smallest size (4 µm) reported to date. This is enabled by a two-dimensional materials-based layer transfer technique15–18 that allows the growth of RGB LEDs of near-submicron thickness on two-dimensional material-coated substrates via remote or van der Waals epitaxy, mechanical release and stacking of LEDs, followed by top-down fabrication. The smallest-ever stack height of around 9 µm is the key enabler for record high µLED array density. We also demonstrate vertical integration of blue µLEDs with silicon membrane transistors for active matrix operation. These results establish routes to creating full-colour µLED displays for augmented and virtual reality, while also offering a generalizable platform for broader classes of three-dimensional integrated devices.
|Number of pages||7|
|Publication status||Published - 2023 Feb 2|
Bibliographical noteFunding Information:
The team at Massachusetts Institute of Technology (MIT) acknowledges support from the National Science Foundation (award no. 2001231), the Defense Advanced Research Projects Agency Young Faculty Award (no. 029584-00001), the Air Force Research Laboratory (award no. FA9453-21-C-0717) and the US Department of Energy’s Office of Energy Efficiency and Renewable Energy under the Solar Energy Technologies Office (award no. DE-EE0008558). The team at MIT also acknowledges support, in part, by LG electronics and Rohm Semiconductor. The team at Georgia Tech-Lorraine acknowledges partial funding by the French National Research Agency under the GANEXT Laboratory of Excellence project. The work by Y.J.H., J.J. and J.C. was supported by a National Research Foundation of Korea grant funded by the Ministry of Science and ICT (nos. 2018K1A4A3A01064272, NRF-2021R1A5A1032996 and 2022M3D1A2050793) and by the Ministry of Education (no. 2022R1A6C101A774).
© 2023, The Author(s), under exclusive licence to Springer Nature Limited.
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