a mosaic tio 2 A method for improving the luminous efficiency of LEDs by periodic arrays of nanorod clusters

Abstract

The invention discloses a method for improving the luminous efficiency of an LED by employing embedded TiO2 nanorod cluster periodic arrays. The method comprises the following steps of (1) preparing an epitaxial wafer of the LED; (2) producing a photoresist and SiO2 double-layer periodic hole graphic template on a p-type GaN layer of the epitaxial wafer; (3) etching p-type GaN periodic holes; (4)producing embedded TiO2 seed layers which are periodically arranged; (5) growing embedded TiO2 nanorod cluster graphic arrays in p-type GaN by using an acid heating method; (6) evaporating ITO; and (7) producing a uniplanar electrode LED core, with a p electrode and an n electrode, of a complete structure. According to the method, the fastness of TiO2 nanorod clusters on the LED is improved through embedding the TiO2 nanorod clusters into the p-type GaN layer, light extraction is improved through the light scattering effect of the TiO2 nanorod cluster graphic arrays, high extending current iskept by using an ITO network structure among the TiO2 nanorod clusters, the luminous efficiency of the LED is significantly improved, and meanwhile, good electric property is also kept.

Description

technical field [0001] The invention relates to a method for improving the luminous efficiency of a light-emitting diode (LED) by using a titanium dioxide (TiO2) nanorod cluster periodic array embedded in p-GaN and embedded between ITO and p-GaN layers, and belongs to the field of optoelectronic technology. Background technique [0002] With the development of optoelectronic technology, the luminous efficiency of semiconductor lighting LEDs has set new records every year. The luminous range of GaN-based LEDs covers the blue-violet region, and GaN-based blue LEDs are the core of a new generation of "green" white light sources. However, there is still a big gap between the actual luminous efficiency of GaN-based LEDs and its theoretical maximum efficiency, and the research on improving the luminous efficiency of LEDs is a current research hotspot. [0003] LED luminous efficiency is determined by LED internal quantum efficiency (ηint) and light extraction efficiency (ηextr) (...

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Problems solved by technology

[0007] Aiming at the defects and problems of weak adhesion and easy peeling of TiO2 nanorod arrays, the present invention innovatively proposes a simple and low-cost mosaic periodic array of TiO2 nanorod clusters in combination with the patterned structure and the growth characteristics of TiO2 nanorods A method for improving LED luminous efficiency. This method periodically digs p-type GaN holes, fills the TiO2 seed layer by sputtering in the p-type GaN periodic holes, and re-grows TiO2 nanorod clusters. The TiO2 nanorod clusters grown by this method are periodically arrayed and mosaic Into p-type GaN, the binding force between TiO2 nanorod clusters and GaN is greatly improved, and the TiO2 nanorods are not easy to peel off, which improves the structural stability; the grown TiO2 nanorod clusters are periodically embedded in the ITO current spreading layer and the p-type GaN layer Among them, the light scattering effect of the TiO2 nanorod pattern array is used to increase the light output to improve the LED luminous efficiency. At the same time, the ITO network structure between the TiO2 nanorod array patterns and grown on the p-type GaN layer is used to take into account the high expansion current. The invention includes the following steps:

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