Silicon TPV Cell Air-Bridge Structure for Out-of-Band Photon Loss
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Solution Overview
Problem
Existing thermophotovoltaic cells using materials like InGaAs and InSb face scalability limitations and high manufacturing costs, necessitating the development of silicon-based cells with improved efficiency and reduced energy loss from out-of-band photons.
Innovation Solution
An optoelectronic device with an integrated air bridge is fabricated using a silicon wafer with lateral p-n junctions, featuring a reflector, spacer layer, and thermophotovoltaic cell, where the spacer layer includes cavities filled with air or other materials to enhance reflectivity and minimize energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional TPV materials like InGaAs or InSb are used, then power conversion efficiency can be achieved, but scalability is limited and manufacturing cost increases
Solution Approach 1:
The patent replaces expensive conventional TPV materials (InGaAs, InSb) with silicon, which is abundant, inexpensive, and compatible with existing semiconductor manufacturing infrastructure. This substitution maintains acceptable power conversion efficiency while dramatically reducing material costs and enabling scalable production through standard silicon processing techniques.
Solution Approach 2:
The invention modifies the optical and electrical parameters of silicon to optimize it for TPV applications. This includes engineering the silicon bandgap through doping, creating lateral p-n junctions for charge separation, and designing specific contact geometries to enhance carrier collection. These parameter adjustments enable silicon to function effectively as a TPV material despite its traditionally lower efficiency compared to specialized materials.
2Ease of manufacture
If silicon-based TPV cells are used to reduce manufacturing cost, then scalability improves, but power conversion efficiency may decrease due to higher bandgap
Solution Approach 1:
The patent implements lateral p-n junctions that create localized regions of different doping types within the silicon structure. This local differentiation enables efficient charge separation at specific interfaces while maintaining the overall silicon material advantages. The junctions are positioned strategically to maximize carrier separation efficiency without requiring bulk material changes.
Solution Approach 2:
The invention creates a composite structure combining silicon with metal contacts and dielectric layers to form a multi-functional device. The metal contacts provide low-resistance pathways for charge collection, while the dielectric layers enable tunneling contacts that reduce recombination losses. This composite approach compensates for silicon's higher bandgap limitation while preserving its manufacturing advantages.
3Ease of manufacture
If out-of-band photons are not managed, then manufacturing remains simple, but energy loss from unabsorbed photons increases
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the silicon absorber and the metal back contact. This layer serves multiple functions: it enables tunneling contacts that facilitate charge extraction, reduces parasitic absorption of out-of-band photons, and maintains electrical isolation. The intermediary layer is integrated into the fabrication process without significantly increasing manufacturing complexity.
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
The silicon-based thermophotovoltaic cell achieves high power conversion efficiency by minimizing out-of-band photon loss and series resistance, with improved reflectivity and reduced manufacturing costs.
Implementation Method 1
converting radiated photons from the hot emitter by blackbody radiation into electricity
Implementation Method 2
thermophotovoltaic cell is configured to convert radiating thermal energy incident thereon into electrical energy
Implementation Method 3
engineering the reflectivity of the cell can help improve the power conversion efficiency by minimizing the energy loss from unabsorbed out-of-band (OOB) photons
Implementation Method 4
the spacer layer includes a cavity which extends between the reflector and the thermophotovoltaic cell
Data Source
AI summary
Techniques are presented for fabricating optoelectronic devices with integrated air bridges for improved efficiency. The optoelectronic device includes: a reflector disposed on the substrate; a spacer layer disposed on the reflector; and a thermophotovoltaic cell disposed on to the spacer layer, such that the spacer layer is arranged between the reflector and the thermophotovoltaic cell and the spacer layer includes a cavity which extends between the reflector and the thermophotovoltaic cell. Of note, the thermophotovoltaic cell is comprised of silicon material with one or more lateral p-n junctions formed therein.