Nitride Semiconductor Light Emitting Device With Tunnel Junction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high electrical resistance of p-type semiconductor layers in light emitting devices, particularly those using nitride semiconductors, affects the device's characteristics due to carrier scattering and Mg diffusion, leading to increased leakage currents and reduced light emission efficiency.
Innovation Solution
A light emitting device structure is implemented with a tunnel junction layer and a p-type semiconductor layer formed on a nitride semiconductor substrate, where the active layer is formed after the tunnel junction layer, reducing damage and allowing for a lower p-type semiconductor layer thickness, and using InGaN layers to suppress Mg diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a p-type semiconductor layer is used to form a current-confined structure, then carrier scattering is reduced and light emission efficiency is improved, but electrical resistance increases significantly
Solution Approach 1:
An n-type semiconductor layer is introduced as an intermediary between the substrate and the p-type semiconductor layer. This n-type layer serves as a mediator that provides a low-resistance current path while allowing the p-type layer to maintain its current-confined structure for efficient light emission. The n-type layer compensates for the high resistance of the p-type layer without disrupting the current confinement geometry.
2Object-generated harmful factors
If the p-type semiconductor layer thickness is reduced to minimize Mg diffusion, then light emission efficiency improves, but current confinement capability deteriorates
Solution Approach 1:
The current confinement function is segmented between two layers: the n-type semiconductor layer provides the primary current path with thin thickness to minimize Mg diffusion, while the p-type semiconductor layer maintains the current-confined structure geometry. This segmentation allows each layer to optimize its thickness for its specific function without compromising the other.
3Manufacturing precision
If growth temperature is increased to improve crystal quality, then light emission efficiency improves, but Mg diffusion increases
Solution Approach 1:
The n-type semiconductor layer acts as a thermal buffer and Mg diffusion barrier. It allows the p-type layer to be grown at higher temperatures for improved crystal quality while the n-type layer absorbs excess thermal energy and prevents Mg atoms from diffusing into critical regions, thus decoupling the temperature-dependent crystal quality from Mg diffusion.
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
This configuration reduces electrical resistance, minimizes leakage currents, and enhances light emission efficiency by controlling the growth temperatures and impurity profiles, resulting in improved device performance.
Implementation Method 1
a tunnel junction layer disposed on a part of the first n-type semiconductor layer
Data Source
AI summary
A light emitting device includes: a first n-type semiconductor layer disposed on a substrate; a tunnel junction layer disposed on a part of the first n-type semiconductor layer; a p-type semiconductor layer disposed on the first n-type semiconductor layer and covering the tunnel junction layer; an active layer disposed on the p-type semiconductor layer; and a second n-type semiconductor layer disposed on the active layer.