Drift Mobility Measurements in Porous Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
L. Tsybeskov ◽  
C. Peng ◽  
P. M. Fauchet ◽  
Q. Gu ◽  
E. A. Schiff

AbstractModulated electroluminescence (EL) measurements performed on a series of porous silicon (PSi) diodes are presented. The maximum response time of the devices scales with the square of the PSi layer thickness and inversely with the applied forward bias voltage. These scaling results indicate that the maximum response time is a carrier transit time from which a drift mobility μ of 10−4 cm2/Vs is deduced at room temperature. Time-of-flight transport measurements on PSi are in qualitative agreement with this value for μ in addition, they identify μ as the electron mobility and show that transport is dispersive, in contrast to the interpretation of the modulated EL experiments.

2017 ◽  
Vol 79 (4) ◽  
Author(s):  
Suharjito Suharjito ◽  
Adrianus B. Kurnadi

Database for Online Transaction Processing (OLTP) application is used by almost every corporations that has adopted computerisation to support their operational day to day business. Compression in the storage or file-systems layer has not been widely adopted for OLTP database because of the concern that it might decrease database performance. OLTP compression in the database layer is available commercially but it has a significant licence cost that reduces the cost saving of compression. In this research, transparent file-system compression with LZ4, LZJB and ZLE algorithm have been tested to improve performance of OLTP application. Using Swing-bench as the benchmark tool and Oracle database 12c, The result indicated that on OLTP workload, LZJB was the most optimal compression algorithm with performance improvement up to 49% and consistent reduction of maximum response time and CPU utilisation overhead, while LZ4 was the compression with the highest compression ratio and ZLE was the compression with the lowest CPU utilisation overhead. In terms of compression ratio, LZ4 can deliver the highest compression ratio which is 5.32, followed by LZJB, 4.92; and ZLE, 1.76. Furthermore, it is found that there is indeed a risk of reduced performance and/or an increase of maximum response time.


1992 ◽  
Vol 283 ◽  
Author(s):  
V. Petrova-Koch ◽  
T. Muschik ◽  
D. I. Kovalev ◽  
F. Koch ◽  
V. Lehmann

ABSTRACTTime-resolved studies of the visible photoluminescence in porous silicon with three different coverages of the internal surface are reported. We use aged, naturally oxidized porous Si (oxihydride), rapid thermal processed material (oxide) and samples stored in HF (pure hydride). A new, fast luminescence band in the blue-green spectral range and with response time less than 100 ns is observed at room temperature in each of the samples, although with different intensities. The observations prove that this is not an oxide-defect luminescence. We speculate on mechanisms for the origin of the fast luminescence in nanometer-size crystallites of Si.


1996 ◽  
Vol 459 ◽  
Author(s):  
M. C. Poon ◽  
J.K.O. Sin ◽  
H. Wong ◽  
P. G. Han ◽  
W. H. Kwok ◽  
...  

ABSTRACTThis paper presents new organic vapor sensitive device using anodized porous silicon (PS). The sensor has aluminum (Al)/PS/p-Si/Al Schottky diode structure and sensitivity at room temperature in 2600 ppm acetone, methanol, 2-propanol and ethanol is about 4, 5, 10 and 40 times respectively. The sensitivity in 800–2600 ppm ethanol vapor is 2 to 40 times. The diode sensor can be converted into an Al/PS/Al resistor sensor by switching the electrical contacts, and the sensitivity is about 500 times for a humidity change of 43–75%. All sensors have response time of about 0.5 min. The sensitivity is stable with time and the PS sensor can be integrated into VLSI Si devices to form novel microelectronic systems.


2020 ◽  
Vol 1 (1) ◽  
pp. 27-31
Author(s):  
Achmad Haris Afandi ◽  
Putri Anbar Ghalia ◽  
Kistiani Kistiani ◽  
Indri Rahma Sari ◽  
Sri Aswaidar Miza

This study aims to design a prototype Arduino-based portal door controller system device using a smartphone. The making of the tool is done as one of the efforts in advancing technology to provide convenience and comfort through the development of an automated system in the home in the form of automatic portal doors using smartphones. The components used for system design are Arduino REV3 microcontroller module, USB 2.0 type A / B cable (Arduino USB cable), SG90 9g servo motor, red and green LEDs, 220Ω resistor, mini protoboard, connecting cable, jumper cable, and bluetooth module HC06, Powerbank with a capacity of 5600 mAh and a smartphone, while designing software uses Arduino IDE. Based on the results of measurements and testing, the system on the device made is able to open and close the portal door automatically at a maximum distance of 15 meters with a maximum response time of 1 second in open space


2014 ◽  
Vol 23 (4) ◽  
pp. 329-342 ◽  
Author(s):  
Evangelos Mitsakis ◽  
Iraklis Stamos ◽  
Jose Maria Salanova Grau ◽  
Georgia Aifadopoulou

Purpose – The purpose of this paper is to present and apply a methodology that optimally assigns emergency response services (ERS) stations in Peloponnesus, Greece that was severely hit by wildfires in 2007, in an effort to describe the actual emergency response in this disaster and identify disaster management possibilities that can arise from the optimal allocation of the existing fire stations. Design/methodology/approach – The methodology concerns the development of an objective function that aims to minimize maximum and average response times of ERS stations and the evaluation of developed scenarios. Simulated annealing is used for the minimization of the objective function, providing near-optimal solutions with low computation times for medium-scale networks. Findings – The findings concern the comparison of average and maximum response times of ERS stations to hearths of fire, based on their actual and optimal allocation. They reveal an overall reduction in the average and maximum response time by 20 and 30 percent, respectively, for the entire region, while there is a reduction of 15 and 35 percent in the average and maximum response time for the locations affected by the 2007 wildfires. Research limitations/implications – The methodology is formulated as a facility location problem with unitary demand and unlimited capacity in the stations, which means that the allocation does not take into account simultaneous events. Originality/value – The paper fulfills an identified need to apply innovative research solutions to actual case studies in order to identify existing gaps and future disaster management possibilities.


2020 ◽  
Vol 9 (1) ◽  
pp. 13 ◽  
Author(s):  
Marco Pasetti ◽  
Emiliano Sisinni ◽  
Paolo Ferrari ◽  
Stefano Rinaldi ◽  
Alessandro Depari ◽  
...  

The adoption of the distributed generation paradigm is introducing several changes in the design and operation of modern distribution networks. Modern grid codes are becoming more and more complex, and the adoption of smart protection systems is becoming mandatory. However, the adoption of newer and smarter units is only half of the story. Proper communication networks must be provided as well, and the overall costs may become critical. In this work, the adoption of the Long-Range Wide Area Network (LoRaWAN) technology is suggested as a viable approach to implement the coordination of Interface Protection Systems. A proper communication architecture based on the LoRaWAN Class B technology was proposed and evaluated in order to assess its feasibility for the considered application. A scalability analysis was carried out, by computing the number of devices that can be handled by a single LoRaWAN Gateway (GW) and the maximum expected time of response between a triggering event and the arrival of the related coordination command. The results of the study showed that up to 312 devices can be managed by a single GW, by assuring a maximum response time of 22.95 s. A faster maximum response time of 6.2 s is also possible by reducing the number of managed devices to 12.


1996 ◽  
Vol 420 ◽  
Author(s):  
M. W. M van Cleef ◽  
M. W. H. Philippens ◽  
F. A. Rubinelli ◽  
M. Kolter ◽  
R. E. I. Schropp

AbstractIn the present paper we show results of dark current-voltage measurements performed on p+ a- SiC:H/n c-Si heterojunction diodes at various temperatures (100–400K). We investigated the voltage derivative of these J-V curves in order to the distinguish possible current transport mechanisms. It was found that for low temperatures (<300K), the current is determined by recombination of carriers in the crystalline silicon, whereas at high temperature (>300 K), by a tunnelling mechanism. At room temperature, both mechanisms contribute to the current. By using an equivalent circuit model and detailed numerical simulations we have interpreted our experimental characteristics. The simulations done at room temperature, show that at low forward bias voltage the current is controlled by recombination in the crystalline silicon and that at high forward bias voltage by a combination of multi-step tunnelling and a-SiC:H series resistance. For interface state densities equal to or higher than 1012 cm−2, the recombination was found to be dominated by the states at the amorphous-crystalline silicon interface.


2000 ◽  
Vol 623 ◽  
Author(s):  
Hiromichi Ohta ◽  
Ken-Ichi Kawamura ◽  
Masahiro Orita ◽  
Nobuhiko Sarukura ◽  
Masahiro Hirano ◽  
...  

AbstractRoom temperature operation of UV LED is realized for the first time using a hetero p-n junction composed of transparent conductive oxides, p-SrCu2O2 and n-ZnO. Ni/SrCu2O2/ZnO/ITO multi-layered film was epitaxially grown on an extremely flat YSZ (111) surface by a PLD. The grown films were processed by a conventional photolithography, followed by reactive ion etching to fabricate p-n junction diode. The resultant device exhibited rectifying I-V characteristics inherent to p-n junction whose turn-on voltage was about 1.5V. A relatively sharp electro-luminescence band centered at 382nm was generated when applying the forward bias voltage larger than the turn-on voltage of 3V. The red shift in the EL peak was noticed from that of photo-luminescence (377nm), which was most likely due to the difference in the excited state density between the emission processes. The EL band is attributed to transition in ZnO, probably to that associated with electron-hole plasma. The photo-voltage was also generated when the p-n junction was irradiated with UV light of which energy coincided with both exciton and band-to-band transitions in ZnO.


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