Fig. 1. Schematic illustrations of the fabrication process flow and lateral overgrowth for asymmetric pyramids.

Fig. 2. (a) Optical images emitted by 405 nm laser and filtered by 450 nm filter; (b) PL intensity of samples 1, 2, 3, and 4; and (c) wavelength distribution for sample 2.

Fig. 3. Cross-section HAADF-STEM images of the point (a) at the semipolar facet, (b) at the edge of (0001) polar facet, (c) at the central part of (0001) facet, and (d) the area in between. The insert image (e) is the SEM image of the cross-section.

Fig. 4. Temporal decay maps of (a) planar LEDs, (b) a single pyramid, and (c) an asymmetric pyramid. TRPL decay curves measured at room temperature for (d) different samples at the main emission wavelength and (e) an asymmetric pyramid with several characteristic peaks.

Fig. 5. Raman spectra recorded on the lateral overgrowth (LO) window, wing, and edge region, accompanied by a planar LED as a reference. The inset displays the recording of the spectra.

Fig. 6. Calculated energy band diagrams (a) at equilibrium and (b) under forward bias. (c) Electron and hole wave functions and (d) the radiative recombination rate of LO asymmetric pyramid and planar LED.