LED Quantum Well Thickness for Low Current Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LEDs struggle to maintain high quantum efficiency at low injection currents, particularly below 1 mA, due to low charge density leading to increased non-radiative recombination and reduced light generation efficiency in low power applications.
Innovation Solution
A semiconductor structure with a single quantum well of specific thickness (2 nm to 10 nm) between barrier regions, which achieves sufficient charge density at low injection currents, and optionally omits aluminum to further reduce non-radiative recombination, enhancing radiative recombination rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional LED structures are used, then high quantum efficiency can be achieved at high injection currents, but quantum efficiency drops significantly at low injection currents below 1 mA
Solution Approach 1:
The patent changes the physical parameters of the active region by reducing quantum well thickness from conventional values (20-50 nm) to ultra-thin values (2-10 nm). This parameter change increases charge carrier confinement and charge density at low injection currents, thereby maintaining high quantum efficiency in low-power applications while preserving high-current performance
Solution Approach 2:
The patent transitions from multiple quantum wells (vertical stacking) to a single ultra-thin quantum well, changing the dimensional arrangement of the active region. This dimensional simplification reduces non-radiative recombination pathways and enhances radiative recombination efficiency, enabling high quantum efficiency across both low and high current ranges
2Illumination intensity
If quantum well thickness is increased to improve light emission, then charge density increases, but non-radiative recombination increases more, reducing quantum efficiency at low currents
Solution Approach 1:
The patent optimizes the quantum well thickness parameter to an ultra-thin range (2-10 nm), which creates strong quantum confinement effects. This confinement increases the overlap between electron and hole wavefunctions, enhancing radiative recombination rates while limiting the total number of non-radiative recombination centers, thus improving quantum efficiency at low currents
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 improves quantum efficiency at low injection currents, achieving peak efficiency at currents ten times smaller than conventional LEDs, with reduced non-radiative recombination and increased light emission.
Implementation Method 1
forming a single quantum well at a preselected thickness between the first barrier region and the second barrier region. The preselected thickness can be selected to achieve a predetermined charge density in the quantum well.
Implementation Method 2
Light emission is caused by the spontaneous recombination of electrons and holes.
Implementation Method 3
The semiconductor structure includes a first barrier region, a second barrier region, and a single quantum well having a preselected thickness between the first barrier region and the second barrier region.
Data Source
AI summary
Provided is a light emitting semiconductor structure that operates as a light emitting diode (LED). In embodiments of the invention, the light emitting semiconductor structure includes a first barrier region, a second barrier region, and a single quantum well having a preselected thickness between the first barrier region and the second barrier region. The preselected thickness according to embodiments is selected to achieve a predetermined charge density in the quantum well. The predetermined charge density according to embodiments results from a predetermined bias current applied to the semiconductor structure. The predetermined bias current according to embodiments comprises less than about 1 mA.