Unveiling the physical mechanism of sidewall surfaces in GaN-based micro-LEDs: a first-principles calculations

The physical properties of the sidewall surface behavior play a critical role in their optoelectronic performance of GaNbased Micro-LEDs. This study combines first-principles calculations with a detailed analysis of the electronic and optical properties, to elucidate the physical mechanism governing the surface characteristics of non-polar GaN (1-100) and semipolar GaN (10-11) planes. The study reveals that the (1-100) surface with its lower surface energy and non-polar characteristics, is structurally more stable than the (10-11) surface. In contrast to the (10-11) surface where surface reconstruction induces N-N bonding and thereby carrier leakage, the (1-100) surface retains excellent semiconductor properties. The localized surface states, superior optical absorption, and high spectral limit efficiency collectively suggest that selectively exposing the (1-100) crystal plane via etching processes is a promising strategy to enhance Micro-LED device performance.