Michael Man - Academia.edu (original) (raw)
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Leibniz Institute for Age Research - Fritz LipmannInstitute
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Papers by Michael Man
Conference on Lasers and Electro-Optics, 2017
Transfer of electrons through semiconductor heterojunctions is the key process in all electronics... more Transfer of electrons through semiconductor heterojunctions is the key process in all electronics. Here we make movies of electron dynamics in InSe/GaAs through time and spectrally-resolved photoemission electron microscopy, bringing insights to this fundamental process.
Bulletin of the American Physical Society, 2021
Bulletin of the American Physical Society, 2005
Proceedings of the International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics, 2019
Bulletin of the American Physical Society, Mar 6, 2015
hertz (THz) emission properties from bow-tie antennas fabricated on a femtosecondlaser-ablated, s... more hertz (THz) emission properties from bow-tie antennas fabricated on a femtosecondlaser-ablated, semi-insulating gallium arsenide (SI-GaAs) photoconductor are investigated. The ablated material demonstrates increased photoabsorption resulting in increased photocurrent leading to a more efficient optical to THz efficiency. We use THz time-domain spectroscopy (THz-TDS) in order to compare the relative efficiency of the two fabricated devices. The influence of the excitation power and applied bias on the antennas electrodes for both ablated and non-ablated substrates is studied, highlighting the better performances of the ablated devices. A 60% enhancement in THz emission amplitude is observed in the frequency range 0.5-4 THz of the ablated SI-GaAs antenna, compared to untreated SI-GaAs. Our experimental results are in agreement with Drude-Lorentz numerical simulations using previously reported absorption and photocurrent properties of femtosecond laser ablated SI-GaAs based photoconductors. This material treatment provides a new way to achieve THz-TDS systems based on SI-GaAs antennas with an improved signal-to-noise ratio.
ACS nano, Jan 13, 2015
The ability to synthesize high-quality samples over large areas and at low cost is one of the big... more The ability to synthesize high-quality samples over large areas and at low cost is one of the biggest challenges during the developmental stage of any novel material. While chemical vapor deposition (CVD) methods provide a promising low-cost route for CMOS compatible, large-scale growth of materials, it often falls short of the high-quality demands in nanoelectronics and optoelectronics. We present large-scale CVD synthesis of single- and few-layered MoS2 using direct vapor-phase sulfurization of MoO2, which enables us to obtain extremely high-quality single-crystal monolayer MoS2 samples with field-effect mobility exceeding 30 cm(2)/(V s) in monolayers. These samples can be readily synthesized on a variety of substrates, and demonstrate a high-degree of optoelectronic uniformity in Raman and photoluminescence mapping over entire crystals with areas exceeding hundreds of square micrometers. Because of their high crystalline quality, Raman spectroscopy on these samples reveal a range...
Proceedings of the International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics, 2019
Conference on Lasers and Electro-Optics, 2017
Transfer of electrons through semiconductor heterojunctions is the key process in all electronics... more Transfer of electrons through semiconductor heterojunctions is the key process in all electronics. Here we make movies of electron dynamics in InSe/GaAs through time and spectrally-resolved photoemission electron microscopy, bringing insights to this fundamental process.
Bulletin of the American Physical Society, 2021
Bulletin of the American Physical Society, 2005
Proceedings of the International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics, 2019
Bulletin of the American Physical Society, Mar 6, 2015
hertz (THz) emission properties from bow-tie antennas fabricated on a femtosecondlaser-ablated, s... more hertz (THz) emission properties from bow-tie antennas fabricated on a femtosecondlaser-ablated, semi-insulating gallium arsenide (SI-GaAs) photoconductor are investigated. The ablated material demonstrates increased photoabsorption resulting in increased photocurrent leading to a more efficient optical to THz efficiency. We use THz time-domain spectroscopy (THz-TDS) in order to compare the relative efficiency of the two fabricated devices. The influence of the excitation power and applied bias on the antennas electrodes for both ablated and non-ablated substrates is studied, highlighting the better performances of the ablated devices. A 60% enhancement in THz emission amplitude is observed in the frequency range 0.5-4 THz of the ablated SI-GaAs antenna, compared to untreated SI-GaAs. Our experimental results are in agreement with Drude-Lorentz numerical simulations using previously reported absorption and photocurrent properties of femtosecond laser ablated SI-GaAs based photoconductors. This material treatment provides a new way to achieve THz-TDS systems based on SI-GaAs antennas with an improved signal-to-noise ratio.
ACS nano, Jan 13, 2015
The ability to synthesize high-quality samples over large areas and at low cost is one of the big... more The ability to synthesize high-quality samples over large areas and at low cost is one of the biggest challenges during the developmental stage of any novel material. While chemical vapor deposition (CVD) methods provide a promising low-cost route for CMOS compatible, large-scale growth of materials, it often falls short of the high-quality demands in nanoelectronics and optoelectronics. We present large-scale CVD synthesis of single- and few-layered MoS2 using direct vapor-phase sulfurization of MoO2, which enables us to obtain extremely high-quality single-crystal monolayer MoS2 samples with field-effect mobility exceeding 30 cm(2)/(V s) in monolayers. These samples can be readily synthesized on a variety of substrates, and demonstrate a high-degree of optoelectronic uniformity in Raman and photoluminescence mapping over entire crystals with areas exceeding hundreds of square micrometers. Because of their high crystalline quality, Raman spectroscopy on these samples reveal a range...
Proceedings of the International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics, 2019