Many applications in space weather and in space situational awareness require continuous solar sp... more Many applications in space weather and in space situational awareness require continuous solar spectral irradiance measurements in the UV, and to a lesser degree in the visible band. Most space-borne solar radiometers are made out of two different parts: (i) a front filter that selects the passband and (ii) a detector that is usually based on silicon technology. Both are prone to degradation, which may be caused either by the degradation of the filter coating due to local deposition or to structural changes, or by the degradation of the silicon detector by solar radiative and energetic particle fluxes. In this study, we provide a theoretical analysis of the filter degradation that is caused by structural changes such as pinholes; contamination-induced degradation will not be considered. We then propose a new instrumental concept, which is expected to overcome, at least partially, these problems. We show how most of the solar UV spectrum can be reconstructed from the measurement of only five spectral bands. This instrumental concept outperforms present spectrometers in terms of degradation. This new concept in addition overcomes the need for silicon-based detectors, which are replaced by wide band gap material detectors. Front filters, which can contribute to in-flight degradation, therefore are not required, except for the extreme-UV (EUV) range. With a small weight and a low telemetry, this concept may also have applications in solar physics, in astrophysics and in planetology.
Solar Physics and Space Weather Instrumentation IV, 2011
Membranes a few hundred nanometers thick are used in EUV optics to make, for example, beams split... more Membranes a few hundred nanometers thick are used in EUV optics to make, for example, beams splitters or passband filters. Despite their necessity in numerous applications these components are, because of their thinness, extremely fragile and their implementation in space instruments is always difficult. The authors are developing thin film filters for the Full Sun Imager, one of the EUV telescopes on board the Solar Orbiter mission with objectives of high optical efficiency and mechanical strength. These filters are specifically designed to isolate one or the other of the two passbands (17.4 and 30.4 nm) reflected by the telescope's dual band mirror coating. In this paper we present the optical properties of the prototype components.
Sensors, Cameras, and Systems for Industrial and Scientific Applications XIII, 2012
This paper describes a back-side illuminated 1 Megapixel CMOS image sensor made in 0.18 m CMOS p... more This paper describes a back-side illuminated 1 Megapixel CMOS image sensor made in 0.18 m CMOS process for EUV detection. The sensor applied a so-call "dual-transfer" scheme to achieve low noise, high dynamic range. The EUV sensitivity is achieved with backside illumination use SOI-based solution. The epitaxial silicon layer is thinned down to less than 3m. The sensor is tested and characterized at 5nm to 30nm illumination. At 17.4nm targeted wavelength, the detector external QE (exclude quantum yield factor) reaches almost 60%. The detector reaches read noise of 1.2 ph-(@17.4nm), i.e. close to performance of EUV photon counting.
Device and Process Technologies for MEMS and Microelectronics II, 2001
Using silicon technology, our approach to tunable VCSEL uses a micromachined suspended deformable... more Using silicon technology, our approach to tunable VCSEL uses a micromachined suspended deformable membrane that also functions as the top mirror above the semiconductor cavity by an airgap. Here, we report the design and first results of a microelectromechanical tunable VCSEL whose frequency is centered around 1300nm.
Abstract We present the first measurement results from hybrid AlGaN-on-Si-based Extreme Ultraviol... more Abstract We present the first measurement results from hybrid AlGaN-on-Si-based Extreme Ultraviolet (EUV) imagers with 10 μm pixel-to-pixel pitch. The 256× 256 backside illuminated Focal Plane Arrays (FPAs) were hybridized to dedicated Si-based CMOS Readouts (ROICs). The AlGaN active layer with 40% Al concentration provides an intrinsic rejection of wavelengths larger than 280 nm (solar blindness), together with enhanced radiation hardness (1). Sensitivity in Deep UV (DUV), Far UV (FUV) and Extreme UV (EUV) was ...
2014 IEEE Radiation Effects Data Workshop (REDW), 2014
For next space-based ultraviolet (UV) solar radiometers, we propose a design based on subsystem c... more For next space-based ultraviolet (UV) solar radiometers, we propose a design based on subsystem components that are selected according to lessons learned from previous flying missions and ground irradiation campaigns. UV interference filters inherited from space-based solar missions show strong degradation caused by structural changes that lead to an important decrease of visible light rejection. Wide bandgap semiconductors (WBGS) are used for the photodetectors: innovative metal-semiconductor-metal (MSM) based on Aluminum Nitride (AlN) and Diamond-based PIN photodetectors were developed, characterized and compared to the commonly used silicon photodiode technology (AXUV and SXUV types). Insignificant degradation of the WBGS basedphotodetector performances were observed after exposure to protons of 14.4 MeV energy showing a good radiation tolerance up to fluences of 1x10 11 p+/cm 2 . Onboard calibration strategy based on UV LEDs are used as well to distinguish the detector's drift from inevitable degradations of the optical front filters.
We report on the utilization of the two-photon induced free carrier generation in a diamond pin-t... more We report on the utilization of the two-photon induced free carrier generation in a diamond pin-type photodiode to record fringeresolved second-order autocorrelations of femtosecond pulses in the UV. Measurements in photovoltaic mode are performed at the second and third harmonic of a Ti:sapphire laser ( 0 401nm λ = and 0 265 λ = nm) with pulse energies down to about 2 nJ. The band gap of diamond of 5.5 eV sets a short wavelength limit at about 225 nm. Combined with the simultaneously recorded linear autocorrelation the spectral phase is reconstructed employing an iterative algorithm.
A Comment on the Letter by M. J. Holland and K. Burnett, Phys. Rev. Lett.PRLTAO0031-9007 71, 1355... more A Comment on the Letter by M. J. Holland and K. Burnett, Phys. Rev. Lett.PRLTAO0031-9007 71, 1355 (1993)10.1103/PhysRevLett.71.1355. The authors of the Letter offer a Reply.
... 65, 030101 2002 ; ? f J. Fiurasek, ibid. 65, 053818 2002 ; g CC Gerry, A. Benmoussa, and RA C... more ... 65, 030101 2002 ; ? f J. Fiurasek, ibid. 65, 053818 2002 ; g CC Gerry, A. Benmoussa, and RA Campos, ibid. 66, 013804 2002 . 5 RA Campos, BEA Saleh, and MC Teich, Phys. Rev. A 40, 1371 1989 . 6 B. Yurke, SL McCall, and JR Klauder, Phys. Rev. A 33, 4033 1986 . ...
New pin-photodiode and metal–semiconductor–metal (MSM) photoconductor devices based on diamond ma... more New pin-photodiode and metal–semiconductor–metal (MSM) photoconductor devices based on diamond material have been produced showing high responsivity around 200 nm. LYRA, the Large Yield RAdiometer, will use such detectors for the first time for a solar physics space instrument. A set of measurement campaigns was carried out to obtain their XUV-to-VIS characterization (responsivity, linearity, stability and homogeneity). The diamond pin and MSM photodetectors exhibit a high responsivity of 27 mA/W around 200 nm and demonstrate a visible rejection ratio (200 nm versus 500 nm) of six and four orders of magnitude, respectively. We show that these diamond photodetectors are sensitive sensors for the wavelength range of interest (1 nm to 220 nm), stable within a few percent, with a good linearity and moderate homogeneity.
IEEE International Conference on Micro Electro Mechanical Systems, 2010
In this work, we report on a novel microfabrication process suitable for macroelectronics, flexib... more In this work, we report on a novel microfabrication process suitable for macroelectronics, flexible electronics and biological applications. It consists of the embedding of high aspect ratio vertical nanosheets of materials on the surface of polydimethylsiloxane (PDMS) by using a reusable template and a dry-transfer process. Vertical Au-nanosheets (Au-NS) were successfully transferred onto the PDMS surface. Although a high density of embedded vertical nanosheets on the PDMS, the optical properties of the PDMS sheet in transmission were high enough for a low cost and high-resolution flexible photomask application. Sub-micron photolithography was demonstrated using inexpensive UV mask aligner and photoresist.
We report on the fabrication of extreme ultraviolet (EUV) hybrid imagers with backside-illuminate... more We report on the fabrication of extreme ultraviolet (EUV) hybrid imagers with backside-illuminated detector chip based on aluminum gallium nitride (AlGaN) layers grown on silicon and integrated with CMOS readout chip. The focal plane array (FPA) size is 256 × 256 pixels with 10-μm pixel-to-pixel pitch. The devices were characterized at wavelengths from 300 down to 1 nm using synchrotron radiation. An upper cutoff wavelength of 280 nm was observed, as expected from the AlGaN active layer composition (40% Al). Thus, the imagers have a high rejection ratio of the near UV and visible radiation. Moreover, no degradation due to proton irradiation was observed for 60-MeV energy and 5 ·1010 protons/cm2 dose. Furthermore, devices with thin silicon substrate layer that is intentionally left were fabricated, and response only in the EUV range was observed. These results demonstrate the possibility of achieving high-resolution EUV imaging with AlGaN-based FPAs, which is very promising for high-end industrial, scientific, and space applications.
High quality ohmic contacts were realized in order to obtain an AlGaN/GaN high electron mobility ... more High quality ohmic contacts were realized in order to obtain an AlGaN/GaN high electron mobility transistor (HEMT) on different substrates (Si, Al2O3, SiC). A metallization scheme based on Ti/Al/Ni/Au was used. The ohmic contacts were obtained using an optimized rapid thermal annealing (RTA) at temperature as high as 900 °C for 30 s in a N2 atmosphere up to the two dimensional electron gas (2DEG). The piezoelectric stress, measured by microRaman spectroscopy, reveals to be dependent on the distance between the transmission line model (TLM) patterns on Si substrate grown by molecular beam epitaxy (MBE). This should be related to the non-linearity of the total resistance (Rt) measured on the largest spacing between two electrodes. After a long thermal treatment at 500 °C for 2000 h, the ohmic contact shows a very stable behaviour.
For the Extreme Ultraviolet Imager (EUI) of the Solar Orbiter mission, to be launched in 2017, co... more For the Extreme Ultraviolet Imager (EUI) of the Solar Orbiter mission, to be launched in 2017, complementary metal oxide semiconductor (CMOS) active pixel sensor (APS) prototypes have been developed with several test pixel designs. A set of measurements was carried out to evaluate their performance characteristics in visible and in EUV wavelengths. We present the results of measurement campaigns that lead to the selection of a preferred pixel design in regard to the scientific performance requirements of the EUI Flight Model detectors, i.e. back-thinned CMOS APS devices of 2048 x 2048 and 3072 x 3072 pixels formats with a 10 µm pixel pitch.
We report on the fabrication of Extreme Ultraviolet (EUV) hybrid imagers with backside illuminate... more We report on the fabrication of Extreme Ultraviolet (EUV) hybrid imagers with backside illuminated detector chip based on aluminum gallium nitride (AlGaN) layers grown on silicon and integrated with CMOS readout chip. The Focal Plane Array (FPA) size is 256x256 pixels with 10 µm pixel-to-pixel pitch. The devices were characterized at wavelengths from 300 nm down to 1 nm using synchrotron radiation. An upper cut off wavelength of 280 nm was observed, as expected from the AlGaN active layer composition (40% Al). Thus, the imagers have a high rejection ratio of the near UV and visible radiation. Moreover, no degradation due to proton irradiation was observed for 60 MeV energy and 5·10 10 protons/cm 2 dose. Furthermore, devices with an intentionally left thin silicon substrate layer were fabricated and response only in the EUV range was observed. These results demonstrate the possibility of achieving high resolution EUV imaging with AlGaN-based FPAs, which is very promising for high-end industrial, scientific and space applications.
Future missions for space astronomy and solar research require innovative vacuum ultraviolet (VUV... more Future missions for space astronomy and solar research require innovative vacuum ultraviolet (VUV) photodetectors. Present UV and VUV detectors exhibit serious limitations in performance, technology complexity and lifetime stability. New developments of metal-semiconductor-metal (MSM) solar-blind photodetectors based on diamond, cubic boron nitride (c-BN), and wurtzite aluminium nitride (AlN) are reported. In the wavelength range of interest, the characteristics of the MSM photodetectors present extremely low dark current, high breakdown voltage, and good responsivity. Diamond, c-BN, and AlN MSM photodetectors are sensitive and stable under UV irradiation. They show a 200 nm to 400 nm rejection ratio of more than four orders of magnitude and demonstrate the advantages of wide band gap materials for VUV radiation detection in space.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2006
We report on experimental results with photodetectors made of diamond. the Large Yield Radiometer... more We report on experimental results with photodetectors made of diamond. the Large Yield Radiometer (LYRA), will use such detectors for the first time for a solar physics space instrument. A (LYRA) set of measurement campaigns was carried out to obtain their XUV-to-VIS characterization (responsivity, linearity, stability, homogeneity). The responsivity has been measured from the XUV to the NIR, in the wavelength range 1-1127 nm (i.e. 1240-1.1 eV). The diamond detectors exhibit a photoresponse varying in the 40-75 mA/W range at 7 nm and demonstrate a visible rejection ratio (200 versus 500 nm) larger than four orders of magnitude. We show that diamond photodetectors are sensitive sensors for VUV photons, stable within a few percent, with a good linearity and moderate homogeneity. r
Many applications in space weather and in space situational awareness require continuous solar sp... more Many applications in space weather and in space situational awareness require continuous solar spectral irradiance measurements in the UV, and to a lesser degree in the visible band. Most space-borne solar radiometers are made out of two different parts: (i) a front filter that selects the passband and (ii) a detector that is usually based on silicon technology. Both are prone to degradation, which may be caused either by the degradation of the filter coating due to local deposition or to structural changes, or by the degradation of the silicon detector by solar radiative and energetic particle fluxes. In this study, we provide a theoretical analysis of the filter degradation that is caused by structural changes such as pinholes; contamination-induced degradation will not be considered. We then propose a new instrumental concept, which is expected to overcome, at least partially, these problems. We show how most of the solar UV spectrum can be reconstructed from the measurement of only five spectral bands. This instrumental concept outperforms present spectrometers in terms of degradation. This new concept in addition overcomes the need for silicon-based detectors, which are replaced by wide band gap material detectors. Front filters, which can contribute to in-flight degradation, therefore are not required, except for the extreme-UV (EUV) range. With a small weight and a low telemetry, this concept may also have applications in solar physics, in astrophysics and in planetology.
Solar Physics and Space Weather Instrumentation IV, 2011
Membranes a few hundred nanometers thick are used in EUV optics to make, for example, beams split... more Membranes a few hundred nanometers thick are used in EUV optics to make, for example, beams splitters or passband filters. Despite their necessity in numerous applications these components are, because of their thinness, extremely fragile and their implementation in space instruments is always difficult. The authors are developing thin film filters for the Full Sun Imager, one of the EUV telescopes on board the Solar Orbiter mission with objectives of high optical efficiency and mechanical strength. These filters are specifically designed to isolate one or the other of the two passbands (17.4 and 30.4 nm) reflected by the telescope's dual band mirror coating. In this paper we present the optical properties of the prototype components.
Sensors, Cameras, and Systems for Industrial and Scientific Applications XIII, 2012
This paper describes a back-side illuminated 1 Megapixel CMOS image sensor made in 0.18 m CMOS p... more This paper describes a back-side illuminated 1 Megapixel CMOS image sensor made in 0.18 m CMOS process for EUV detection. The sensor applied a so-call "dual-transfer" scheme to achieve low noise, high dynamic range. The EUV sensitivity is achieved with backside illumination use SOI-based solution. The epitaxial silicon layer is thinned down to less than 3m. The sensor is tested and characterized at 5nm to 30nm illumination. At 17.4nm targeted wavelength, the detector external QE (exclude quantum yield factor) reaches almost 60%. The detector reaches read noise of 1.2 ph-(@17.4nm), i.e. close to performance of EUV photon counting.
Device and Process Technologies for MEMS and Microelectronics II, 2001
Using silicon technology, our approach to tunable VCSEL uses a micromachined suspended deformable... more Using silicon technology, our approach to tunable VCSEL uses a micromachined suspended deformable membrane that also functions as the top mirror above the semiconductor cavity by an airgap. Here, we report the design and first results of a microelectromechanical tunable VCSEL whose frequency is centered around 1300nm.
Abstract We present the first measurement results from hybrid AlGaN-on-Si-based Extreme Ultraviol... more Abstract We present the first measurement results from hybrid AlGaN-on-Si-based Extreme Ultraviolet (EUV) imagers with 10 μm pixel-to-pixel pitch. The 256× 256 backside illuminated Focal Plane Arrays (FPAs) were hybridized to dedicated Si-based CMOS Readouts (ROICs). The AlGaN active layer with 40% Al concentration provides an intrinsic rejection of wavelengths larger than 280 nm (solar blindness), together with enhanced radiation hardness (1). Sensitivity in Deep UV (DUV), Far UV (FUV) and Extreme UV (EUV) was ...
2014 IEEE Radiation Effects Data Workshop (REDW), 2014
For next space-based ultraviolet (UV) solar radiometers, we propose a design based on subsystem c... more For next space-based ultraviolet (UV) solar radiometers, we propose a design based on subsystem components that are selected according to lessons learned from previous flying missions and ground irradiation campaigns. UV interference filters inherited from space-based solar missions show strong degradation caused by structural changes that lead to an important decrease of visible light rejection. Wide bandgap semiconductors (WBGS) are used for the photodetectors: innovative metal-semiconductor-metal (MSM) based on Aluminum Nitride (AlN) and Diamond-based PIN photodetectors were developed, characterized and compared to the commonly used silicon photodiode technology (AXUV and SXUV types). Insignificant degradation of the WBGS basedphotodetector performances were observed after exposure to protons of 14.4 MeV energy showing a good radiation tolerance up to fluences of 1x10 11 p+/cm 2 . Onboard calibration strategy based on UV LEDs are used as well to distinguish the detector's drift from inevitable degradations of the optical front filters.
We report on the utilization of the two-photon induced free carrier generation in a diamond pin-t... more We report on the utilization of the two-photon induced free carrier generation in a diamond pin-type photodiode to record fringeresolved second-order autocorrelations of femtosecond pulses in the UV. Measurements in photovoltaic mode are performed at the second and third harmonic of a Ti:sapphire laser ( 0 401nm λ = and 0 265 λ = nm) with pulse energies down to about 2 nJ. The band gap of diamond of 5.5 eV sets a short wavelength limit at about 225 nm. Combined with the simultaneously recorded linear autocorrelation the spectral phase is reconstructed employing an iterative algorithm.
A Comment on the Letter by M. J. Holland and K. Burnett, Phys. Rev. Lett.PRLTAO0031-9007 71, 1355... more A Comment on the Letter by M. J. Holland and K. Burnett, Phys. Rev. Lett.PRLTAO0031-9007 71, 1355 (1993)10.1103/PhysRevLett.71.1355. The authors of the Letter offer a Reply.
... 65, 030101 2002 ; ? f J. Fiurasek, ibid. 65, 053818 2002 ; g CC Gerry, A. Benmoussa, and RA C... more ... 65, 030101 2002 ; ? f J. Fiurasek, ibid. 65, 053818 2002 ; g CC Gerry, A. Benmoussa, and RA Campos, ibid. 66, 013804 2002 . 5 RA Campos, BEA Saleh, and MC Teich, Phys. Rev. A 40, 1371 1989 . 6 B. Yurke, SL McCall, and JR Klauder, Phys. Rev. A 33, 4033 1986 . ...
New pin-photodiode and metal–semiconductor–metal (MSM) photoconductor devices based on diamond ma... more New pin-photodiode and metal–semiconductor–metal (MSM) photoconductor devices based on diamond material have been produced showing high responsivity around 200 nm. LYRA, the Large Yield RAdiometer, will use such detectors for the first time for a solar physics space instrument. A set of measurement campaigns was carried out to obtain their XUV-to-VIS characterization (responsivity, linearity, stability and homogeneity). The diamond pin and MSM photodetectors exhibit a high responsivity of 27 mA/W around 200 nm and demonstrate a visible rejection ratio (200 nm versus 500 nm) of six and four orders of magnitude, respectively. We show that these diamond photodetectors are sensitive sensors for the wavelength range of interest (1 nm to 220 nm), stable within a few percent, with a good linearity and moderate homogeneity.
IEEE International Conference on Micro Electro Mechanical Systems, 2010
In this work, we report on a novel microfabrication process suitable for macroelectronics, flexib... more In this work, we report on a novel microfabrication process suitable for macroelectronics, flexible electronics and biological applications. It consists of the embedding of high aspect ratio vertical nanosheets of materials on the surface of polydimethylsiloxane (PDMS) by using a reusable template and a dry-transfer process. Vertical Au-nanosheets (Au-NS) were successfully transferred onto the PDMS surface. Although a high density of embedded vertical nanosheets on the PDMS, the optical properties of the PDMS sheet in transmission were high enough for a low cost and high-resolution flexible photomask application. Sub-micron photolithography was demonstrated using inexpensive UV mask aligner and photoresist.
We report on the fabrication of extreme ultraviolet (EUV) hybrid imagers with backside-illuminate... more We report on the fabrication of extreme ultraviolet (EUV) hybrid imagers with backside-illuminated detector chip based on aluminum gallium nitride (AlGaN) layers grown on silicon and integrated with CMOS readout chip. The focal plane array (FPA) size is 256 × 256 pixels with 10-μm pixel-to-pixel pitch. The devices were characterized at wavelengths from 300 down to 1 nm using synchrotron radiation. An upper cutoff wavelength of 280 nm was observed, as expected from the AlGaN active layer composition (40% Al). Thus, the imagers have a high rejection ratio of the near UV and visible radiation. Moreover, no degradation due to proton irradiation was observed for 60-MeV energy and 5 ·1010 protons/cm2 dose. Furthermore, devices with thin silicon substrate layer that is intentionally left were fabricated, and response only in the EUV range was observed. These results demonstrate the possibility of achieving high-resolution EUV imaging with AlGaN-based FPAs, which is very promising for high-end industrial, scientific, and space applications.
High quality ohmic contacts were realized in order to obtain an AlGaN/GaN high electron mobility ... more High quality ohmic contacts were realized in order to obtain an AlGaN/GaN high electron mobility transistor (HEMT) on different substrates (Si, Al2O3, SiC). A metallization scheme based on Ti/Al/Ni/Au was used. The ohmic contacts were obtained using an optimized rapid thermal annealing (RTA) at temperature as high as 900 °C for 30 s in a N2 atmosphere up to the two dimensional electron gas (2DEG). The piezoelectric stress, measured by microRaman spectroscopy, reveals to be dependent on the distance between the transmission line model (TLM) patterns on Si substrate grown by molecular beam epitaxy (MBE). This should be related to the non-linearity of the total resistance (Rt) measured on the largest spacing between two electrodes. After a long thermal treatment at 500 °C for 2000 h, the ohmic contact shows a very stable behaviour.
For the Extreme Ultraviolet Imager (EUI) of the Solar Orbiter mission, to be launched in 2017, co... more For the Extreme Ultraviolet Imager (EUI) of the Solar Orbiter mission, to be launched in 2017, complementary metal oxide semiconductor (CMOS) active pixel sensor (APS) prototypes have been developed with several test pixel designs. A set of measurements was carried out to evaluate their performance characteristics in visible and in EUV wavelengths. We present the results of measurement campaigns that lead to the selection of a preferred pixel design in regard to the scientific performance requirements of the EUI Flight Model detectors, i.e. back-thinned CMOS APS devices of 2048 x 2048 and 3072 x 3072 pixels formats with a 10 µm pixel pitch.
We report on the fabrication of Extreme Ultraviolet (EUV) hybrid imagers with backside illuminate... more We report on the fabrication of Extreme Ultraviolet (EUV) hybrid imagers with backside illuminated detector chip based on aluminum gallium nitride (AlGaN) layers grown on silicon and integrated with CMOS readout chip. The Focal Plane Array (FPA) size is 256x256 pixels with 10 µm pixel-to-pixel pitch. The devices were characterized at wavelengths from 300 nm down to 1 nm using synchrotron radiation. An upper cut off wavelength of 280 nm was observed, as expected from the AlGaN active layer composition (40% Al). Thus, the imagers have a high rejection ratio of the near UV and visible radiation. Moreover, no degradation due to proton irradiation was observed for 60 MeV energy and 5·10 10 protons/cm 2 dose. Furthermore, devices with an intentionally left thin silicon substrate layer were fabricated and response only in the EUV range was observed. These results demonstrate the possibility of achieving high resolution EUV imaging with AlGaN-based FPAs, which is very promising for high-end industrial, scientific and space applications.
Future missions for space astronomy and solar research require innovative vacuum ultraviolet (VUV... more Future missions for space astronomy and solar research require innovative vacuum ultraviolet (VUV) photodetectors. Present UV and VUV detectors exhibit serious limitations in performance, technology complexity and lifetime stability. New developments of metal-semiconductor-metal (MSM) solar-blind photodetectors based on diamond, cubic boron nitride (c-BN), and wurtzite aluminium nitride (AlN) are reported. In the wavelength range of interest, the characteristics of the MSM photodetectors present extremely low dark current, high breakdown voltage, and good responsivity. Diamond, c-BN, and AlN MSM photodetectors are sensitive and stable under UV irradiation. They show a 200 nm to 400 nm rejection ratio of more than four orders of magnitude and demonstrate the advantages of wide band gap materials for VUV radiation detection in space.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2006
We report on experimental results with photodetectors made of diamond. the Large Yield Radiometer... more We report on experimental results with photodetectors made of diamond. the Large Yield Radiometer (LYRA), will use such detectors for the first time for a solar physics space instrument. A (LYRA) set of measurement campaigns was carried out to obtain their XUV-to-VIS characterization (responsivity, linearity, stability, homogeneity). The responsivity has been measured from the XUV to the NIR, in the wavelength range 1-1127 nm (i.e. 1240-1.1 eV). The diamond detectors exhibit a photoresponse varying in the 40-75 mA/W range at 7 nm and demonstrate a visible rejection ratio (200 versus 500 nm) larger than four orders of magnitude. We show that diamond photodetectors are sensitive sensors for VUV photons, stable within a few percent, with a good linearity and moderate homogeneity. r
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