| 초록 |
Three-dimensional (3D) nano/micro-structures made of various semiconductor materials have recently been studied and proven to have superior performances compared with those of their bulk counterparts. In particular, nano/micro-structured materials are known to have extraordinary optical properties such as negative reflectivity and near perfect absorbance. In order to fully exploit the potential benefits of such a nano/micro-structures, however, it is essential to establish the fabrication and/or synthesis of artificially-controlled 3D structures. Here, we report on the fabrication and characteristic of 3D light emitting diodes (LEDs) based on GaN/InGaN epitaxial layers on 3D nano/micro-architectured ZnO crystal Templates grown by hydrothermal method. To do this, we first established control of preferential growth direction of ZnO nanostructures by polarity-selective crystallization, during low-temperature solution-phase synthesis. This feature was further combined with multistage epitaxial growth of nanocrystal constituents, producing 3D, single crystalline ZnO crystal arrays. Finally, hetero-epitaxial overgrowth of GaN and InxGa1-xN layer on the ZnO templates was achieved by minimizing the chemical damage during metal-organic vapor phase epitaxial growth. The resulting GaN/InGaN multilayered structures were used to fabricate 3D micro LEDs that can potentially be suitable for novel and multi-functional optoelectronic devices. |
