Semiconductor Light Emitting Device Intermediate Oxidation Barrier
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Solution Overview
Problem
Semiconductor light emitting devices experience a gradual rise in forward voltage over time, leading to increased heat dissipation and reduced lifespan, which affects their reliability and durability, especially in applications requiring low power consumption and long life.
Innovation Solution
Incorporating a transparent electrically-conducting layer with an intermediate layer of Nb2O5 between the reflective structure and the semiconductor layers, which suppresses the rise in forward voltage and enhances the device's resistance to oxidation, thereby improving reliability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent electrically-conducting layer is used in the semiconductor light emitting device, then electrical conductivity is improved, but the layer is prone to oxidation which causes forward voltage to rise over time
Solution Approach 1:
An intermediate layer is introduced between the transparent electrically-conducting layer and the reflective layer. This intermediate layer acts as a protective barrier that prevents oxidation of the transparent electrically-conducting layer, thereby maintaining stable electrical conductivity and forward voltage characteristics over time while preserving the electrical conductivity function.
2Duration of action of stationary object
If the forward voltage rises over time, then the device continues to operate, but heat dissipation increases reducing lifespan
Solution Approach 1:
The intermediate layer is provided in advance to prevent oxidation of the transparent electrically-conducting layer before it occurs. By preventing oxidation beforehand, the electrical conductivity is maintained stable, forward voltage rise is suppressed, and consequently heat dissipation is reduced, extending the device lifespan.
3Productivity
If a reflective structure is formed to improve light emission efficiency, then light output is improved, but the interface between layers becomes susceptible to oxidation
Solution Approach 1:
The intermediate layer is positioned between the transparent electrically-conducting layer and the reflective layer, serving as a protective barrier that prevents oxidation at this critical interface. This maintains both the light emission efficiency provided by the reflective structure and the long-term reliability of the layer interface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively stabilizes the forward voltage, enhancing the semiconductor light emitting device's lifespan and reliability by preventing oxidation and maintaining efficient operation over time.
Implementation Method 1
The intermediate layer 17 is formed of a material which contains an element with larger ionization tendency than the reflective layer 16. According to this construction, since the intermediate layer is interposed between the transparent electrically-conducting layer and the reflecting structure, it can be suppressed that the forward voltage in the operation gradually rises with the use time of the semiconductor light emitting devices.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A semiconductor light emitting device includes first and second semiconductor layers, an active region, a transparent electrically-conducting layer 13, a reflecting structure 20, and a first electrode. The second semiconductor layer has a conductivity different from the first semiconductor layer. The active region is arranged between the first and second semiconductor layers. The transparent electrically-conducting layer 13 is arranged on or above the first semiconductor layer. The reflecting structure 20 is arranged on or above the transparent electrically-conducting layer 13. The first electrode is arranged on or above the reflecting structure 20, and electrically connected to the first semiconductor layer. The reflecting structure 20 includes at least a reflective layer 16. An intermediate layer 17 is interposed between the transparent electrically-conducting layer 13 and the reflecting structure 20. The intermediate layer 17 is formed of a material containing an element with larger ionization tendency than the reflective layer 16.