New insights on large area flexible position sensitive detectors (original) (raw)
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Production and characterization of large area flexible thin film position sensitive detectors
Thin Solid Films, 2001
Flexible large area thin film position sensitive detectors based on amorphous silicon technology were prepared on polyimide substrates using the conventional plasma enhanced chemical vapor deposition technique. The sensors were characterized by spectral response, illuminated I᎐V characteristics position detectability measurements and atomic force microscopy. The obtained one-dimensional position sensors, 5-mm wide and 60-mm long, presented a maximum spectral response at 600 nm, an open circuit voltage of 0.6 V and a position detectability with a correlation of 0.9989 associated to a S.D. of 1 = 10 y2 , comparable to those produced on glass substrates. ᮊ
Flexible a-Si:H Position-Sensitive Detectors
Proceedings of the IEEE, 2005
Flexible and large area (5 mm 2 80 mm with an active length of 70 mm) position-sensitive detectors (PSDs) deposited onto polymeric substrates (polyimide-Kapton VN) have been fabricated. The optimized structure presented is based on a heterojunction of amorphous silicon (a-Si : H)/ZnO : Al. The sensors were characterized by spectral response, photocurrent dependence as a function of light intensity, and position detection measurements. The set of data obtained on one-dimensional PSDs based on the heterojunction show excellent performances with a maximum spectral response of 0.12 A/W at 500 nm and a nonlinearity of 610% over 70-mm length. The produced sensors present a nonlinearity higher than those ones produced on glass substrates, due to the different thermal coefficients exhibited by the polymer and the a-Si : H film. In order to prove this behavior, it was measured the defect density obtained by the constant photocurrent method on a-Si : H thin films deposited on polymeric substrates and bent with different radii of curvature.
Flexible large area thin film position sensitive detectors
Sensors and Actuators A: Physical, 2000
Large area thin film position sensitive detectors based on amorphous silicon technology have been prepared on polyimide substrates using the conventional plasma-enhanced chemical vapour deposition. The sensors have been characterised by spectral response, light intensity dependence and linearity measurements in a bent state in order to evaluate the properties in real working conditions. The Ž . obtained one-dimensional 1D position sensors with 10 mm width and 20 mm length present a non-linearity of "1% which are comparable to the ones produced on glass substrates. q
Journal of Non-Crystalline Solids, 2002
In this paper we present results concerning the optimisation of the electronic and mechanical properties presented by amorphous silicon (a-Si:H) thin films produced on polyimide (Kapton â VN) substrates with different thicknesses (25, 50 and 75 lm) by the plasma enhanced chemical vapour deposition (PECVD) technique. The purpose of this study is to obtain a low defect density as well as low residual stresses (specially at the interface) in order to provide good performances for large area (10 mm wide by 80 mm long) flexible position sensitive detectors. The electrical and optical properties presented by the films will be correlated to the sensor characteristics. The properties of samples have been measured by dark/photoconductivity, constant photocurrent measurements (CPM) and the results have been compared with films deposited on Corning 7059 glass substrates during the same run deposition. The residual stresses were measured using an active optical triangulation and angle resolved scattering. The preliminary results indicate that the thinner polymeric substrate with 25 lm presents the highest density of states, which is associated to the residual stresses and strains associated within the film. Ó
Large-Area Position-Sensitive Detector Based on Amorphous-Silicon Technology
Amorphous Silicon Technology-1993, 1993
We have developed a rectangular dual-axis large area Position Sensitive Detector (PSD), with 5 em x 5 em detection arca, based on PIN hydrogenated amorphous silicon (a-Si:H) technology, produced by Plasma Enhanced Chemical Vapor Deposition (PECVO). The metal. eontacts are located in the four edges of the detected area, two of them located on the back side of the ITO/PIN/Al structure and the others two loeated in the front side. The key factors of the detectors resolution and linearity are the thickness uniformity of the different layers, the geometry and the contacts location. Besides that, edge effects on the sensor's comer disturb the linearity of the detector. In this paper we present results concerning the linearity of the detector as well as its optoelectronic characteristics and the role of the i-Iayer thickness on the final sensor performances.
In this paper, novel, very simple and low-cost thin film position sensitive detectors (TFPSDs) which employ indium tin oxide (ITO)-cadmium sulfide (CdS)-Au structures are presented. Different from the existed PSDs those based on lateral photovoltage effect, the proposed sensor is operated in principle of photoconductive effect. CdS film is chosen as the photosensitive layer since its excellent photoconductive property, low cost and suitable for depositing on different type substrates with large areas. In the present study, CdS films are deposited on silicon substrates by using rf magnetron sputtering at room temperature. After that, the prepared CdS films were annealed at different temperatures for 50 min in N2 ambient and a rigorous analysis was presented on the surface topography, and photoconductive properties by scanning electron microscopy and semiconductor characteristics analyzer. The test results shows that the film annealed at 400 °C has the best photoconductive property. Moreover, the finite-element method was used to study the relationship between the Aluminium (Al) electrode shape and the linearity of PSD. Three different type PSDs (quadrilateral, rectangular-shaped and pillow-shaped) were designed and simulated. The simulation results indicate that the quadrilateral electrode is suitable for large-area PSDs, whereas the rectangular-shaped and pillow-shaped electrodes can be used to realize small-area PSDs. The measurement results shows that the non-linearities of three type PSDs with dimensions of 10 × 10 mm are respectively 2.106, 3.594, and 3.55 %, which verify the conclusion deduced from the simulation results.
IEEE Transactions on Electron Devices, 1996
In this work, we present a model to interpret the steady-state and the dynamic detection limits of 1-D Thin Film Position Sensitive Detectors (1-D TFPSD) based on p-i-n a-Si:H devices. From this, an equivalent electric circuit is derived and the predicted values are compared with the experimental results obtained in 1-D TFPSD devices,\ with different sizes. The model is also able to determine the device characteristics that influence the spatial limits and the response time of the device.
Super linear position sensitive detectors using MIS structures
Optical Materials, 2005
This work reports on the fabrication process and performances presented by metal insulator semiconductor (MIS) linear position sensitive detectors (PSD) with an active length of 6 cm. The use of long sensitive areas allows the PSD to achieve higher resolution without the need of a highly accurate light spot integration mechanism. The PSD is built in a multilayered structure consisting of Cr/ a-Si:H (n + doped)/a-Si:H (intrinsic)/SiO x (passivation layer)/Au, where the active a-Si:H layers were deposited by a modified triode plasma enhanced chemical vapour deposition (MTPECVD), which allows the deposition of highly electronic grade material with a low (%1 • 10 15 cm À3) defect density inferred by CPM. The sensor linearity and sensitivity shows dependence on the sensor width to length ratio and on the value of load resistance. Sensitivities of more than 30 mV/cm were achieved with linearity near 99%. Besides that, this type of MIS structure allows an improved spectral response near the UV region and has the maximum response at 540 nm.
Thin Film Position Sensitive Detectors Based on aSi:H Devices
Solid State Phenomena, 1995
The aim of this paper is to present data concerning the performances of position sensitive detectors based on silicon carbide alloys, able to detect the green colour and to compare their performances with the ones exhibit by position sensitive detectors, optimised to detect the red colour. The data achieved show that the device linearity is quite high with spatial resolution errors below AE1%. #
New two-dimensional position sensitive silicon detector with good position linearity and resolution
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1989
A two-dimensional position sensitive silicon detector (PSSD) with a good linear response, consisting of a square ton-implanted resistive anode with a boundary of an additional resistive-strip electrode, was newly developed. Linearity and resolution for the PSSD were investigated using 40 MeV helium and 95 MeV nitrogen ion beams. The PSSD has an effective area of 45 mm X 45 mm, a thickness of 400 win, a junction capacitance of 500 pF, a surface resistance of the ton-implanted resistive anode of 18 kuo and a resistance of the strip line of 1.4 kQ. The nonlineanties and resolutions (FWHM) of the position were 0.75% and 1.97 mm for 40 MeV helium tons obtained by 6 ws pulse shaping, and 0.47% and 0.71 mm for 95 MeV nitrogen ions obtained by 12~ts pulse shaping, respectively.