Top-emitting light emitting diodes and method of manufacturing thereof

Abstract

Provided are a top-emitting nitride-based light emitting device having an n-type clad layer, an active layer and a p-type clad layer sequentially stacked thereon, comprising an interface modification layer formed on the p-type clad layer and a transparent conductive thin film layer made up of a transparent conductive material formed on the interface modification layer; and a process for preparing the same. In accordance with the top-emitting nitride-based light emitting device of the present invention and a process for preparing the same, there are provided advantages such as improved ohmic contact with the p-type clad layer, leading to increased wire bonding efficiency and yield upon packaging the light emitting device, capability to improve luminous efficiency and life span of the device due to low specific contact resistance and excellent current- voltage properties.

Description

technical field [0001] The invention relates to a top-emitting nitride-based light-emitting device and a preparation method thereof. More particularly, the present invention relates to a top-emission nitride-based light-emitting device having improved ohmic characteristics and luminous efficiency and a method of manufacturing the same. Background technique [0002] Currently, transparent conductive films are used in a variety of applications in a variety of fields, including optoelectronics, display, and energy industries. [0003] In the field of light-emitting devices, the development of transparent conductive ohmic electrode structures capable of smooth hole injection and high-efficiency light-emitting functions is now being actively developed worldwide. [0004] Currently, transparent conducting oxides (TCOs) and transparent conducting nitrides (TCNs) are the most actively explored and studied transparent conductive thin-film materials. [0005] Transparent conducting ...

AI Technical Summary

Problems solved by technology

[0008] First, since the above-mentioned transparent conductive film has a high sheet resistance value close to about 100 Ω / unit area, such a large The resistance characteristics of the light-emitting device make it difficult to achieve current spreading in the horizontal direction (parallel to the layer-layer interface) of the light-emitting device, and it is also difficult to perform smooth hole injection in the vertical direction, thus enabling high brightness with large area and high capacity Light-emitting devices are difficult to realize

[0009] Second, since the above-mentioned transparent conductive film has high reflectivity and absorptivity to light emitted by GaN-based light-emitting diodes, the luminous efficiency of diodes formed from it is low

[0010] Third, transparent conductive films such as indium tin oxide (ITO) and titanium nitride (TiN) have relatively low work functions, so it is difficult to form an ohmic contact by direct contact with p-type GaN

[0023] 1. The low hole concentration of p-type GaN and thus over 10 4 High sheet resistance value in Ω / unit area

[0024] 2. Due to the lack of highly transparent electrode materials with relatively high work functions compared to p-type GaN, a high Schottky barrier height and width is formed at the interface between p-type GaN and the electrode , thus making it difficult to perform smooth hole injection in the vertical direction

[0025] 3. The reciprocal relationship between electrical properties and optical properties in most materials, and thus, generally transparent electrodes with high light transmittance have high sheet resistance values, resulting in current flow in the horizontal direction The sharp drop in spread

[0026] 4. Due to the direct deposition of the p-type gallium nitride upper transparent conductive thin film layer, an insulating gallium oxide (Ga 2 o 3 ), leading to the deterioration of the electrical characteristics of the light-emitting device

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