Radek Roucka - Academia.edu (original) (raw)

Uploads

Papers by Radek Roucka

LEOS 2007 - IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings, 2007

ABSTRACT In summary, epitaxial Ge1-xSnx films with hole mobilities as high as 600 cm2V-1s-1 were ... more ABSTRACT In summary, epitaxial Ge1-xSnx films with hole mobilities as high as 600 cm2V-1s-1 were deposited on Si(100) substrates by UHV-CVD and used to fabricate photoconductor devices employing standard semiconductor processing steps. Performance measurements of the produced device provided feedback for improvement of the Ge1-xSnx material quality during the growth. Photoconductor devices showed maximum 0.5% decrease of the resistance upon irradiation by 1.55 mum laser light with 5 mW power.

2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 2016

IEEE Journal of Photovoltaics, 2016

In this study, p-i-n heterostructure photodiodes were fabricated from Ge0.98Sn0.02 films grown di... more In this study, p-i-n heterostructure photodiodes were fabricated from Ge0.98Sn0.02 films grown directly on Si substrates using complementary metal-oxide-semiconductor (CMOS) compatible processes. The devices characterized with respect to their dark currents and their quantum efficiency in the near IR. The structures were grown on boron-doped (p-type) Si(100) with resistivity 0.01 phicm. A 350nm thick layer of intrinsic Ge0.98Sn0.02 was deposited

Applied Physics Letters, Dec 11, 2006

ABSTRACT High quality heteroepitaxial HfxZr1−xB2 (x = 0–1) buffers were grown directly on Si(111)... more ABSTRACT High quality heteroepitaxial HfxZr1−xB2 (x = 0–1) buffers were grown directly on Si(111). The compositional dependence of the film structure and ab initio elastic constants were used to show that hexagonal HfxZr1−xB2 possess tensile in-plane strain (0.5%) as grown. High quality HfB2 films were also grown on strain compensating ZrB2-buffered Si(111). Initial reflectivity measurements of thick ZrB2 films agree with first principles calculations which predict that the reflectivity of HfB2 increases by 20% relative to ZrB2 in the 2–8 eV range. These tunable structural, thermoelastic, and optical properties suggest that HfxZr1−xB2 templates should be suitable for broad integration of III nitrides with Si.

The application of silicon photonic technologies to optical telecommunications requires the devel... more The application of silicon photonic technologies to optical telecommunications requires the development of near-infrared detectors monolithically integrated to the Si platform. Recently, new low-temperature CVD techniques have been developed for growth of high-quality epitaxial films of Ge, Ge1-ySny, and SixGe1-x-ySny directly on Si. In this poster, we present details on the growth of these films, optimization of processes for the fabrication of photonic devices, and results from some prototype p-i-n heterostructure devices.

ABSTRACT A system was developed for measuring photocurrent as a function of incident power and wa... more ABSTRACT A system was developed for measuring photocurrent as a function of incident power and wavelength in new Ge1-ySny semiconductor alloys. Detectors based on this material are expected to operate at wavelengths longer than possible in Ge-detectors due to the lowering of the band gap induced by Sn. Photocurrent measurements were taken on several alloys with incident light at 1.55 mum for a large range of intensities. Additionally, the absorption coefficient of these samples was determined as a function of wavelength.

2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC), 2015

Solid State Sciences, Nov 1, 2002

Semiconductors D 8000 Novel Synthetic Pathways to Wide Bandgap Semiconductors in the Si-C-Al-N Sy... more Semiconductors D 8000 Novel Synthetic Pathways to Wide Bandgap Semiconductors in the Si-C-Al-N System.-Epitaxial SiCAlN films with single-phase wurtzite structures are grown on 6H-SiC by molecular beam epitaxy via reactions of H 3 SiCN and Al atoms at unprecedented low temperatures in the range of 550-750°C. The material has a fundamental bandgap of 3.2 eV consistent with theoretical calculations of the band structure. It is suggested that bandgap engineering between 3.2 and 4.5 eV is readily attainable by increasing the AlN content in the films. The microhardness of these films is comparable with that of sapphire. The SiCAlN films can be grown directly on Si(111) substrates via self assembled Si-Al-ON templates and buffer layers. The Si-Al-ON materials are ideal candidates as semiconducting nucleation layers for the integration of nitride semiconductors such as AlN and GaN with silicon.

LEOS 2007 - IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings, 2007

ABSTRACT In summary, epitaxial Ge1-xSnx films with hole mobilities as high as 600 cm2V-1s-1 were ... more ABSTRACT In summary, epitaxial Ge1-xSnx films with hole mobilities as high as 600 cm2V-1s-1 were deposited on Si(100) substrates by UHV-CVD and used to fabricate photoconductor devices employing standard semiconductor processing steps. Performance measurements of the produced device provided feedback for improvement of the Ge1-xSnx material quality during the growth. Photoconductor devices showed maximum 0.5% decrease of the resistance upon irradiation by 1.55 mum laser light with 5 mW power.

2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 2016

IEEE Journal of Photovoltaics, 2016

In this study, p-i-n heterostructure photodiodes were fabricated from Ge0.98Sn0.02 films grown di... more In this study, p-i-n heterostructure photodiodes were fabricated from Ge0.98Sn0.02 films grown directly on Si substrates using complementary metal-oxide-semiconductor (CMOS) compatible processes. The devices characterized with respect to their dark currents and their quantum efficiency in the near IR. The structures were grown on boron-doped (p-type) Si(100) with resistivity 0.01 phicm. A 350nm thick layer of intrinsic Ge0.98Sn0.02 was deposited

Applied Physics Letters, Dec 11, 2006

ABSTRACT High quality heteroepitaxial HfxZr1−xB2 (x = 0–1) buffers were grown directly on Si(111)... more ABSTRACT High quality heteroepitaxial HfxZr1−xB2 (x = 0–1) buffers were grown directly on Si(111). The compositional dependence of the film structure and ab initio elastic constants were used to show that hexagonal HfxZr1−xB2 possess tensile in-plane strain (0.5%) as grown. High quality HfB2 films were also grown on strain compensating ZrB2-buffered Si(111). Initial reflectivity measurements of thick ZrB2 films agree with first principles calculations which predict that the reflectivity of HfB2 increases by 20% relative to ZrB2 in the 2–8 eV range. These tunable structural, thermoelastic, and optical properties suggest that HfxZr1−xB2 templates should be suitable for broad integration of III nitrides with Si.

The application of silicon photonic technologies to optical telecommunications requires the devel... more The application of silicon photonic technologies to optical telecommunications requires the development of near-infrared detectors monolithically integrated to the Si platform. Recently, new low-temperature CVD techniques have been developed for growth of high-quality epitaxial films of Ge, Ge1-ySny, and SixGe1-x-ySny directly on Si. In this poster, we present details on the growth of these films, optimization of processes for the fabrication of photonic devices, and results from some prototype p-i-n heterostructure devices.

ABSTRACT A system was developed for measuring photocurrent as a function of incident power and wa... more ABSTRACT A system was developed for measuring photocurrent as a function of incident power and wavelength in new Ge1-ySny semiconductor alloys. Detectors based on this material are expected to operate at wavelengths longer than possible in Ge-detectors due to the lowering of the band gap induced by Sn. Photocurrent measurements were taken on several alloys with incident light at 1.55 mum for a large range of intensities. Additionally, the absorption coefficient of these samples was determined as a function of wavelength.

2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC), 2015

Solid State Sciences, Nov 1, 2002

Semiconductors D 8000 Novel Synthetic Pathways to Wide Bandgap Semiconductors in the Si-C-Al-N Sy... more Semiconductors D 8000 Novel Synthetic Pathways to Wide Bandgap Semiconductors in the Si-C-Al-N System.-Epitaxial SiCAlN films with single-phase wurtzite structures are grown on 6H-SiC by molecular beam epitaxy via reactions of H 3 SiCN and Al atoms at unprecedented low temperatures in the range of 550-750°C. The material has a fundamental bandgap of 3.2 eV consistent with theoretical calculations of the band structure. It is suggested that bandgap engineering between 3.2 and 4.5 eV is readily attainable by increasing the AlN content in the films. The microhardness of these films is comparable with that of sapphire. The SiCAlN films can be grown directly on Si(111) substrates via self assembled Si-Al-ON templates and buffer layers. The Si-Al-ON materials are ideal candidates as semiconducting nucleation layers for the integration of nitride semiconductors such as AlN and GaN with silicon.

Log In