Optoelectronic Layer Structure With Buried Sidewall PN Junction
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Solution Overview
Problem
Small optoelectronic devices face challenges in achieving sufficient brightness due to non-radiative recombination at the edges, which reduces quantum efficiency and creates parasitic pn-junctions that hinder performance.
Innovation Solution
An additional thin n-doped layer is introduced on the lateral surface of the device, forming an artificial pn-junction that buries the previous parasitic junction, reducing non-radiative recombination by increasing the bandgap and resistance, thus minimizing current flow to non-radiative recombination centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Zn diffusion is performed in the outer region to achieve quantum well intermixing, then quantum efficiency is improved, but a parasitic pn-junction is created causing non-radiative recombination
Solution Approach 1:
The harmful parasitic pn-junction is extracted and relocated from the device surface to a buried position within the material structure. By introducing an additional n-doped layer, the pn-junction is moved away from the surface region where non-radiative recombination centers are present, thereby separating the useful quantum well intermixing effect from the harmful surface recombination.
Solution Approach 2:
An additional n-doped layer is introduced as an intermediary element between the p-doped quantum well intermixing region and the n-doped active region. This intermediary layer creates a controlled artificial pn-junction that buries the parasitic junction deeper in the material, away from surface recombination centers, while maintaining the beneficial quantum efficiency improvements.
2Area of stationary object
If the device size is reduced to achieve small form factor, then device integration is improved, but non-radiative recombination at edges increases
Solution Approach 1:
The device structure is modified with local quality variations: an additional n-doped layer is selectively introduced in the outer region where quantum well intermixing is performed, while the central active region maintains its original structure. This localized modification addresses the edge effect problem without affecting the central radiative recombination region, allowing small device area to coexist with high quantum efficiency.
3Object-generated harmful factors
If an additional n-doped layer is introduced to bury the parasitic junction, then non-radiative recombination is reduced, but device complexity increases
Solution Approach 1:
The additional n-doped layer is merged with the existing device structure during the manufacturing process, combining the functions of quantum well intermixing and parasitic junction burial into a single integrated structural element. This merging approach reduces device complexity by consolidating multiple functions into one layer rather than adding separate independent components.
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 significantly reduces non-radiative recombination, enhancing radiative recombination in the central region and improving the efficiency of small optoelectronic devices by minimizing the impact of parasitic pn-junctions and non-radiative recombination centers.
Implementation Method 1
a thin n-doped surface layer is provided on the circumferential sidewall extending from the n-doped layer substantially towards a top of the p-doped layer. The thin n-doped surface layer forms an artificial pn-junction that is substantially parallel to the circumferential sidewall
Implementation Method 2
the surrounding second portion comprises an additional p-type dopant causing a quantum well intermixing in the surrounding second portion. The QWI enlarges the band gap of the quantum wells in this outer area close to the edges of the mesa
Data Source
AI summary
In an embodiment an optoelectronic device includes a layer stack having a circumferential sidewall region and having an n-doped layer, an active region layer deposited on the n-doped layer, the active region layer having a central first portion and a surrounding second portion, a p-doped layer arranged on the active region layer, wherein the surrounding second portion comprises a p-type dopant causing a quantum well intermixing in the surrounding second portion and a thin n-doped surface layer on the circumferential sidewall extending from the n-doped layer substantially towards a top of the p-doped layer thereby forming an artificial pn-junction substantially parallel to the circumferential sidewall region and at least partially within the surrounding second portion and the p-doped layer.