Asymmetric Vertical Current Injection in III-V Electro-Optical Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The configuration of symmetric top and bottom ohmic contacts in III-V optoelectronic devices leads to a weak overlap between the gain profile and the fundamental mode position, resulting in poor performance in terms of output power and threshold currents.
Innovation Solution
An asymmetric electrode configuration is implemented, where the two sets of ohmic contacts are arranged on opposite sides of the median vertical plane, allowing for a more homogeneous electric field and improved overlap between the recombination zone and the fundamental mode position, while maintaining vertical current injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If symmetric top and bottom ohmic contacts are used, then the device structure is simple and manufacturing is easier, but the overlap between gain profile and fundamental mode position is weak resulting in poor output power and high threshold currents
Solution Approach 1:
The patent applies asymmetry by positioning the top and bottom ohmic contacts at different lateral locations relative to the waveguide mode profile. Specifically, one contact is positioned at a first lateral location while the other contact is positioned at a second lateral location, creating an asymmetric current injection pattern that aligns the recombination zone with the fundamental mode position, thereby improving gain overlap and output power
2Power
If asymmetric electrode configuration is used, then the overlap between recombination zone and fundamental mode position is improved resulting in higher output power, but the access resistance increases
Solution Approach 1:
The patent applies local quality by optimizing the electrical properties at different locations. The asymmetric contact configuration is combined with a graded index separate confinement heterostructure that provides localized carrier confinement and field shaping. This allows the device to achieve better mode overlap and reduced access resistance by tailoring the local electrical and optical properties at each contact location and along the current path
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 approach results in higher output power and lower threshold currents, despite increased access resistances, by ensuring balanced electron and hole injection within the mode region.
Implementation Method 1
using an asymmetric electrode configuration makes it possible to shape the electric field such as for it to be laterally more homogeneous
Implementation Method 2
a stack of III-V semiconductor gain materials
Data Source
AI summary
The present invention is notably directed to an electro-optical device. This device has a layer structure, which comprises a stack of III-V semiconductor gain materials, an n-doped layer and a p-doped layer. The III-V materials are stacked along a stacking direction z, which is perpendicular to a main plane of the stack. The n-doped layer extends essentially parallel to the main plane of the stack, on one side thereof. The p-doped layer too extends essentially parallel to this main plane, but on another side thereof. A median vertical plane can be defined in the layer structure, which plane is parallel to the stacking direction z and perpendicular to the main plane of the stack. Now, the device further comprises two sets of ohmic contacts, wherein the ohmic contacts of each set are configured for vertical current injection in the stack of III-V semiconductor gain materials.