Inverted Metamorphic Solar Cell Graded Interlayers

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for manufacturing commercially viable inverted metamorphic multijunction solar cells face challenges in choosing appropriate materials and fabrication steps, leading to inefficiencies and complexities in achieving high energy conversion efficiencies.

Innovation Solution

The use of metamorphic grading interlayers, specifically AlGaInAs with step-graded or monotonically changing lattice constants, to reduce threading dislocations and optimize band gap transitions between lattice mismatched subcells, along with a metal organic chemical vapor deposition (MOCVD) process for high-volume production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If metamorphic grading interlayers with step-graded lattice constants are used to reduce threading dislocations, then manufacturing precision and reliability improve, but device complexity and fabrication difficulty increase

Engineering Contradiction:

Improvethreading dislocation reductionVSAvoidfabrication complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The metamorphic grading interlayer is divided into multiple discrete steps rather than a continuous gradient. Each step has a specific lattice constant and thickness, allowing precise control over dislocation reduction while maintaining manageable fabrication complexity through standardized deposition processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lattice constant is systematically varied across different layers of the metamorphic grading interlayer, creating a gradient that transitions from the substrate lattice constant to the final layer lattice constant. This parameter change enables controlled dislocation management while optimizing band gap transitions between subcells.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If multiple metamorphic layers with optimized band gap combinations are implemented, then energy conversion efficiency improves, but manufacturing complexity and process difficulty increase

Engineering Contradiction:

Improveenergy conversion efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

Each metamorphic layer is designed with specific local properties including particular band gap values (e.g., 1.5 eV-1.6 eV for first graded interlayer, 1.1 eV for second graded interlayer) and specific thicknesses. This local optimization of material properties at different positions in the stack maximizes overall energy conversion efficiency by matching the solar spectrum to appropriate band gaps.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solar cell employs a composite structure combining multiple semiconductor materials with different band gaps and lattice constants. The metamorphic grading interlayers use composite material systems that enable both lattice matching and desired optical properties, achieving high efficiency through the synergistic combination of materials with complementary characteristics.

Inventive Principle:

Principle #40Composite materials

3Productivity

If high-volume production processes like MOCVD are used, then productivity increases, but manufacturing precision and material quality control become more challenging

Engineering Contradiction:

Improvehigh-volume production capabilityVSAvoidmaterial quality control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The metamorphic grading interlayers are designed and optimized in advance with predetermined step structures, thicknesses, and composition gradients. This preliminary design allows the complex multi-layer structure to be fabricated using standardized, repeatable MOCVD processes, enabling high-volume production while maintaining consistent material quality through process control.

Inventive Principle:

Principle #10Preliminary action

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

Significant improvement in conversion efficiency is achieved, with band gap combinations such as 1.5 eV-1.6 eV for the first graded interlayer and 1.1 eV for the second graded interlayer resulting in enhanced energy conversion and reduced manufacturing complexities.

Implementation Method 1

A first graded interlayer, a middle portion including at least one solar subcell; a second graded interlayer... each of which provides a transition in lattice constant between lattice mismatched subcells

Methodology Applied

Scientific EffectCompositional grading:

Implementation Method 2

along with a metal organic chemical vapor deposition (MOCVD) process for high-volume production

Methodology Applied

Scientific EffectMetal organic chemical vapor deposition: Chemical Vapour Deposition

Implementation Method 3

III-V compound semiconductor multijunction devices have greater energy conversion efficiencies... spectral splitting of the incident radiation through the use of a plurality of photovoltaic regions with different band gap energies

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS10381501B2Inverted metamorphic multijunction solar cell with multiple metamorphic layers

Publication Date: 2019.08.13 SOLAERO TECHNOLOGIES CORP

AI summary

The disclosure describes multi-junction solar cell structures that include two or more graded interlayers.