Side-Input GaAs Laser Power Converters With Gradient AlGaAs Waveguide

• Published in: IEEE electron device letters Vol. 43; no. 10; pp. 1717 - 1719
• Main Authors: Khvostikov, Vladimir P., Panchak, Alexander N., Khvostikova, Olga A., Pokrovskiy, Pavel. V.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antireflection coatings; efficiency; Epitaxial growth; Gallium arsenide; Gallium arsenide lasers; Irradiation; laser power converter; Lasers; Liquid phase epitaxy; Liquid phases; Optical fibers; P-n junctions; Photovoltaic; Photovoltaic systems; Power converters; Power lasers; Pulsed lasers; Quantum efficiency; Radiation effects; Semiconductor crystals; Semiconductor lasers; vertical p-n junction; Waveguide lasers; Waveguides
• DOI: 10.1109/LED.2022.3202987
• ISSN: 0741-3106

Vertical p-n junction photovoltaic converters are the subject of this work. In these devices, light is injected into the semiconductor crystal through a side interface. So the current-carrying contacts are continuous. Therefore, the advantages of this design compared to the traditional (horizontal p-n junction) are as follows: simplified post-growth processing and ease of sequential assembly. GaAs photovoltaic converters are of particular interest for converting the light with the wavelength of 850 nm. However, a prototype with a design completely similar to the horizontal one is inoperable due to high surface recombination. Waveguide can be implemented to get around this limitation. So photovoltaic converters with a vertical p-n junction with a GaAs active region and a <inline-formula> <tex-math notation="LaTeX">50~ \mu \text{m} </tex-math></inline-formula> thick AlxGa1-xAs waveguide layer were grown by liquid-phase epitaxy. In the waveguide layer, laser radiation is refracted towards the active region without absorption. The refraction is provided by using a smooth linear change of x from 0.55 to 0.15. The grown samples were tested in practice under pulsed laser irradiation supplied by a <inline-formula> <tex-math notation="LaTeX">50~ \mu \text{m} </tex-math></inline-formula> optical fiber. With the use of an antireflection coating on the photodetector interface, a photoconversion efficiency of 53% was shown at an irradiation power of 92 mW (4.7 kW/cm2) and more than 50% at 190 mW (10 kW/cm2).