Hybrid III-V Photovoltaic Array on Sapphire for High Voltage Power-by-Light
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Solution Overview
Problem
Existing power-by-light systems lack the compact size and capability to deliver high voltages efficiently, which is necessary for advanced space systems, due to limitations in achieving high voltages with III-V PV diodes, particularly with GaAs substrates experiencing leakage currents.
Innovation Solution
A hybrid-integrated III-V semiconductor photovoltaic array is developed, where 10s to 1000s of III-V single wavelength photodiodes are bonded onto an optically transparent substrate, enabling high-voltage operation under monochromatic illumination, using substrates like sapphire that are chemically inert and transparent, allowing for efficient optical power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If III-V PV diodes are used for power-by-light conversion, then conversion efficiency is improved, but output voltage is insufficient
Solution Approach 1:
The PV array is segmented into multiple individual III-V PV diodes (10s to 1000s of diodes) that are hybrid-integrated and series-connected on a transparent substrate. Each diode maintains high conversion efficiency while the series connection of multiple diodes accumulates voltage, resolving the contradiction between efficient conversion and sufficient output voltage.
Solution Approach 2:
The invention transitions from single-diode or few-diode configurations to a two-dimensional array architecture where numerous diodes are arranged and series-connected on the substrate. This dimensional expansion enables voltage multiplication through series connections while preserving the high efficiency characteristics of individual III-V diodes.
2Ease of manufacture
If GaAs substrate is used for III-V PV diodes, then manufacturing is simplified, but leakage currents prevent high voltage operation
Solution Approach 1:
The invention extracts the PV diodes from the GaAs substrate and bonds them onto a transparent substrate. This separation removes the leakage current problem associated with the GaAs substrate while retaining the manufacturing advantages of III-V diodes. The transparent substrate provides electrical isolation necessary for high voltage operation.
Solution Approach 2:
The transparent substrate acts as an intermediary between the III-V diodes and the external environment. It provides electrical isolation that prevents leakage currents while allowing optical transmission, thereby enabling high voltage operation without compromising the diodes' manufacturing simplicity.
3Power
If commercial power-by-light systems are used, then power delivery is achieved, but system volume is too large
Solution Approach 1:
The invention merges the optical transmission function and the photovoltaic conversion function into a single integrated receiver unit. The transparent substrate serves both as the structural support and as the optical window, while the hybrid-integrated diode array provides both electrical isolation and power conversion, eliminating the need for separate components and reducing overall system volume.
Solution Approach 2:
The transparent substrate performs multiple functions simultaneously: it provides structural support, enables optical transmission, provides electrical isolation for high voltage operation, and serves as the mounting platform for the diode array. This multi-functionality reduces the number of separate components needed, thereby reducing system volume.
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 solution enables high-voltage, efficient optical power delivery up to 1000s of volts in a compact package, suitable for harsh environments, by optimizing series/parallel connections and using transparent substrates like sapphire, enhancing the performance of power-by-light systems.
Implementation Method 1
bonded onto an optically transparent substrate... under monochromatic illumination from the transparent substrate side
Implementation Method 2
converted back into electricity by a photovoltaic (PV) diode(s)... 10s-to-1000s of III-V semiconductor single wavelength hybrid-integrated series/parallel-connected photodiodes
Data Source
AI summary
A hybrid-integrated series/parallel-connected photovoltaic diode array employs 10s-to-100s of single-wavelength III-V compound semiconductor photodiodes in an array bonded onto a transparent optical plate through which the array is illuminated by monochromatic light. The power-by-light system receiver enables high-voltage, up to 1000s of volts, optical transmission of power to remote electrical systems in harsh environments.