Fig. 1. PL peak wavelength uniformity map for 2，4，6，8 inch wafers with zero edge exclusion. PL uniformity is very comparable，all around 2 nm in standard deviation except the 8 inch wafer due to non-optimized wafer pocket design^［16］. Reprinted with permission of Springer Nature，copyright（2010）.

Fig. 2. Effect of size reduction on the EQE of GaN-based micro LEDs ^［24］

Fig. 3. Optical representation of monolithically integrated VMOSFET LED device with equivalent circuit design^［28］. Reprinted^{with permission of AIP publishing，copyright（2016）.}

Fig. 4. Optical characteristics of semi-polar（202¯1¯）green LEDs，where（a）peak wavelength and（b）FWHM curves as a function of current densities ^［38］. Reprinted with permission of The Japan Society of Applied Physics，copyright（2013）.

Fig. 5. Optical performance of NR-Micro-LEDs and quantum dots.（a）EL spectra of RGB colors；（b）Color gamut of RGB hybrid QD NR Micro-LEDs，NTSC，and Rec. 2020 ^［45］. Reprinted with permission of Optica Publishing Group，copyright（2019）.

Fig. 6. Plot of power conversion efficiency against current density for the red，green and blue LEDs^［44］. Reprinted with permission of John Wiley and Sons，copyright（2019）.

Fig. 7. （a）Schematic cross section of a MQW with GaN barriers，AlGaN interlayers，and five periods of InGaN quantum wells；（b）2D ball and stick representation of different layers；（c）Interlayer thickness versus relaxation plot；（d）Power density versus efficiency plot showing that 1 nm thick interlayer has the highest efficiency^［44］. Reprinted with permission of John Wiley and Sons，copyright（2019）.

Fig. 8. Schematic of LIFT off process^［70］. Reprinted with permission of Elsevier，copyrigt（2016）.

Fig. 9. Schematic representation of steps involves in elastomer stamp micro-assembly process.（a）Prepare donor substrate；apply rubber stamp；（b）Quickly peel back stamp with objects attached with it；（c）Apply inked stamp to receiving substrate，and（d）with printing object on receiver substrate slowly peel back stamp ^［78］. Reprinted with permission of Springer Nature，copyright（2005）.

Fig. 10. Schematics of（a）roll to roll NIL and（b）roll to plate NIP process.（c）Photograph of 6-inch capable R2R/R2PNIL apparatus ^［76］. Reprinted with permission of American Chemical Society，Copyright（2009）.

Fig. 11. Plots of current density against power conversion efficiency for green LED.（a）Constant v=6×10³ cm·s^-1 and variable a_s/V=4×10¹ to 4×10⁴ cm^-1；（b）Constant a_s/V=4×10⁴ cm^-1 and vs=1，10，100，1 000 cm·s^-1［44］. Reprinted with permission of John Wiley and Sons，Copyright（2019）.

Fig. 12. Computer simulation versus machine learning^［93］. Reprinted with permission of Springer Nature，Copyright（2021）.