Search results for "PHOTODIODES"
showing 5 items of 5 documents
Modification of a commercial atomic force microscopy for low-noise, high-resolution frequency-modulation imaging in liquid environment.
2011
A key issue for high-resolution frequency-modulation atomic force microscopy imaging in liquids is minimizing the frequency noise, which requires a detailed analysis of the corresponding noise contributions. In this paper, we present a detailed description for modifying a commercial atomic force microscope (Bruker MultiMode V with Nanoscope V controller), aiming at atomic-resolution frequency-modulation imaging in ambient and in liquid environment. Care was taken to maintain the AFMs original stability and ease of operation. The new system builds upon an optimized light source, a new photodiode and an entirely new amplifier. Moreover, we introduce a home-built liquid cell and sample holder …
Responsivity measurements of 4H-SiC Schottky photodiodes for UV light monitoring
2014
We report on the design and the electro-optical characterization of a novel class of 4H-SiC vertical Schottky UV detectors, based on the pinch-off surface effect and obtained employing Ni2Si interdigitated strips. We have measured, in dark conditions, the forward and reverse I–V characteristics as a function of the temperature and the C–V characteristics. Responsivity measurements of the devices, as a function of the wavelength (in the 200 – 400 nm range), of the package temperature and of the applied reverse bias are reported. We compared devices featured by different strip pitch size, and found that the 10 μm device pitch exhibits the best results, being the best compromise in terms of fu…
Solar blind AlGaN photodetectors with a very high spectral selectivity
2006
Solar blind detectors based on AlGaN heterostructures grown on sapphire by Molecular Beam Epitaxy and with a dielectric interference filter deposited on the back side are demonstrated to provide record spectral selectivity. Rejection ratios of 2 x 10(4), and better than 5 x 10(4), measured between 280 and 320 nm, are achieved in Metal Semiconductor Metal detectors and Schottky diodes respectively. The whole detector process is fully compatible with low cost array fabrication.
Solar blind detectors based on AlGaN grown on sapphire
2005
Solar blind detectors have been fabricated based on AlGaN heterostructures grown on sapphire by molecular beam epitaxy or chemical vapour deposition. MSM and Schottky detectors were investigated. High performance devices have been obtained thanks to an optimization of the material crystalline quality (including the suppression of cracks) and of the process. We show that the spectral limitations of MSM detectors are dictated by intrinsic phenomena that are analysed in details while the responsivity and detectivity also depends on the technological process with a special emphasis on the geometry of finger and contact pads. One and two dimensional arrays have been fabricated and preliminary re…
Calibration of the photon spectrometer PHOS of the ALICE experiment
2019
Journal of Instrumentation 14(05), P05025 - P05025 (2019). doi:10.1088/1748-0221/14/05/P05025