Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 Using two-step anodized TiO2 nanotubes to increase the collection efficiency of DSSCs at low illumination angles با استفاده از دو مرحله نانولوله آنودایز TiO2 به افزایش بهره وری مجموعه ای از DSSCs در زاویه نور کم 1 7 12929 EN Hamed Reza Arab Bafrani Nano Physics Research Laboratory, Department of Physics, University of Tehran, North Kargar, Tehran, Iran. Yaser Abdi Nano Physics Research Laboratory, Department of Physics, University of Tehran, North Kargar, Tehran, Iran. Journal Article Photonic crystals (PCs) with extraordinary optical properties, can be used to enhance light absorption and improve solar cell’s conversion efficiency. Prohibition of propagation for some particular wavelengths of light in PCs result in increasing the path length of light in working electrode of solar cell that enhance the probability of photon absorption. In our work, we present a two-step anodization method for manufacturing the dye-sensitized solar cells (DSSCs), having a three-dimensional roughness material as working electrode that looks like a semi-photonic crystal mesoporous structure. This approach is a facile one to produce a PC-like structure and it plays a great role in improvement of output power of DSSC. Measurements show that solar cell’s photovoltaic conversion efficiency based on this 3D roughness structure is higher than the conventional DSSC.

https://mjee.modares.ac.ir/article_12929_0ac2e9dc0810e7a46d37c8070285c9ef.pdf

Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 Enhanced Energy harvesting, utilizing ZnO nanosheet based nanogenerator embedded in phononic crystal برداشت انرژی پیشرفته، استفاده از نانوژنراتور بر اساس اکسید روی nanosheet جاسازی شده در بلور فوتونی 9 13 12930 EN Armin Heydari ECE Department of Tarbiat Modares University, Tehran, Iran. Sara Darbari ECE Department of Tarbiat Modares Journal Article In this report, we present a direct current piezoelectric nanogenerator based on ZnO nanosheets, which is driven by ultrasound waves propagating in water. ZnO nanosheets have been grown by hydrothermal method on Al layer as the bottom ohmic contact, while Ni layer serves as the top Schottky contact. Then, we have designed a 1D phononic crystal to realize localized standing wave at the position of nanogenerator, and consequently enhance the energy harvesting performance. The proposed phononic crystal consists of water/steel periodic slabs which are enclosing both sides of the nanogenerator, and the created mid-gap state is matched with the source frequency in the designed structure. Our simulation results confirm that the pressure difference exerted to the nanogenerator is enhanced by a factor of about 12.3, in comparison with the pristine ZnO nanogenerator.

https://mjee.modares.ac.ir/article_12930_f072c02ed22738d28a2d25004b7ecabf.pdf

Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 A wide spectral range Single-Photon Avalanche Diode implemented in 65nm standard CMOS Technology طیف گسترده ای طیفی تک فوتون بهمن دیود در 65nm ریزتر استاندارد CMOS تکنولوژی اجرا 15 20 12931 EN Mohammad Azim Karami Department of Electrical Engineering Iran University of Science and Technology, Tehran, Iran. Iman Ansaripour Department of Electrical Engineering Iran University of Science and Technology, Tehran, Iran. Journal Article This paper presents a wide spectral range Single-Photon Avalanche Diode (SPAD) implemented in 65nm standard CMOS (Complementary Metal Oxide Semiconductor) Technology. The wide wavelength sensitivity is achieved using the p-type substrate layer instead of using a different well implanted inside the substrate. The higher electron impact ionization coefficient in compare with the hole impact ionization coefficient results in an increase in the photon detection probability (PDP) in the larger wavelengths. Low PDP in compare with the older technologies is predictable according to the higher doping profiles of the modern deep-submicron technologies. Both the optical emission from the active region and spectral response detection is measured and analyzed in this paper.

https://mjee.modares.ac.ir/article_12931_d4c074c60c57087c95fd0a17f986210c.pdf

Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 Electro-induced hydrophilicity of hydrogen plasma bombarded Ag/TiO2 nanostructure آبدوستی الکترو ناشی از پلاسما هیدروژن بمباران نقره / TiO2 به نانوساختار 21 27 12932 EN Yaser Abdi Nano-Physics Research Laboratory, Department of Physics, University of Tehr an, Tehran, Iran Salimeh Kimiagar Nano-Physics Research Laboratory, Department of Physics, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Aliakbar Chahe Nano-Physics Research Laboratory, Department of Physics, University of Tehr Journal Article Electro-induced hydrophilicity of the Ag/TiO2 nanostructure has been reported in this study. In this work hydrogen plasma bombarded Ag/TiO2 nanostructure was created using a sequential process including chemical vapor deposition and plasma bombardment. X-ray diffraction and X-ray photoelectron spectroscopy were used to analyze structure and chemical states of the sample. The prepared Ag/TiO2 heterostructure has enhanced visible-light-induced hydrophilicity comparing to pure TiO2. The electro-induced hydrophilicity of the samples was also examined by creating the comb like electrodes on the prepared Ag/TiO2. A super-hydrophilic surface was achieved by applying an electric bias voltage on the electrodes.

https://mjee.modares.ac.ir/article_12932_41884c79b3339f66e8b7e121f785d641.pdf

Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 Gate decorated Field Effect Transistors for high sensitivity pH sensing دروازه تزئین ترانزیستورهای اثر زمینه برای سنجش pH و حساسیت بالا 29 34 12933 EN Mohammadreza Hajmirzaheydarali Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Meharnosh . Sadeghipari Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Samana Soleimani-Amiri Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Mahdi Akbari Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Alireza Shahsafi Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran Hosen Hajhosseini Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Fhatama Salehi Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Shamsedin Mohajerzadeh Nano-electronics Lab, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran. Journal Article We present a micro/nano-machining process to introduce nanostructured poly-silicon layer on the gate region of the pH-sensitive field effect transistors. Decoration of the gate of the field effect transistors by nanostructures plays an important role to improve the sensitivity of the pH-sensitive FETs. Electron beam lithography was exploited to realize the poly-Si nanopillars on the gate surface. Comparison between different micro and nanostructures demonstrates the potential of nanopillars to be utilized on the gate of this device rather than micro-conical structures (different size and shapes) and vertically carbon nanotubes. A high sensitivity of 500 mV/pH has been achieved, through the incorporation of silicon based nanopillars.

https://mjee.modares.ac.ir/article_12933_ad92350e4633462fd6eb5956da8876f2.pdf

Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 Carbon Nanotubes on ITO/Silicon Substrate for Fabrication of Silicon Based Lithium Ion Battery نانولوله های کربنی بر روی بستر ITO/سیلیکن برای ساخت باتری لیتیم یونی بر پایه سیلیکن 35 39 12934 EN Seyed Mahmoud Hosseini Nano-fabricated Energy Devices Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran. Seyed Ali Safiabadi Tali Nano-fabricated Energy Devices Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran Zeinab Sanaee Nano-fabricated Energy Devices Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran. Journal Article Carbon nano tubes are currently used in many modern devices for the improvement they can cause in different applications due to their unique properties. Especially in Lithium ion batteries that are today`s most common rechargeable batteries, CNTs have been utilized and offered certain advantages over commercial electrodes. Here we report utilizing carbon nanotubes grown on a silicon wafer with an ITO barrier layer, as the anode of a Lithium ion battery. CNTs with the average thickness of 90 nm and density of 14.5×108 cm-2 have been grown on the surface of the sample and used as the battery electrode. Fabrication of batteries on silicon wafer makes possible the integration of functional devices along with the power source on the same wafer, which is a considerable advantage. Surface of the sample remained intact after several charge and discharge processes, which is a very critical feature in lithium ion batteries based on silicon. High columbic efficiency of 98% and specific capacity of 0.08 mAh/cm2 was achieved after 8 cycles for our structure.

https://mjee.modares.ac.ir/article_12934_32ce3337fc6684b636381084d6932695.pdf

Tarbiat Modares University The Modares Journal of Electrical Engineering 2228-527X 13 3 2013 11 01 . A Facile Solution Based Nickel Deposition Method for the Formation of Vertically Aligned Carbon Nanotubes روشی ساده برای لایه نشانی نیکل مبتنی بر محلول جهت ایجاد نانولوله های کربنی عمودی 41 46 12935 EN Seyed Mahmod Hosseini Nano-fabricated Energy Devices Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran. Alireza Mashayekhi Nano-fabricated Energy Devices Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran. Zaenab Sanaee Thin Film and Nano-electronics Laboratory, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran Shamsoadin Mohajerzadeh Thin Film and Nano-electronics Laboratory, Nano-electronics Center of Excellence, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran Journal Article A novel chemical solution deposition approach is reported for the deposition of nickel catalyst, which is a required step for the growth of carbon nanotubes (CNTs). In this work, after catalyst coating, vertically aligned CNTs have been grown on the silicon oxide and silicon surfaces. The results were studied using field emission scanning electron microscopy (SEM), Raman and X-ray diffraction. This technique has a high selectivity over the size of the catalyst nanoparticles, which results in the simple controlling of the average diameter of grown CNTs in the range of 30 to 150 nm. In addition, this approach leads to a more conformal coating on the surface of the sample in comparison with traditional vacuum-based deposition techniques, enabling the growth of CNTs on highly rough surfaces. The proposed catalyst deposition technique is a fast, inexpensive and simple Nickel catalyst deposition method that can significantly facilitate the growth process of CNTs

https://mjee.modares.ac.ir/article_12935_c8f1cc280396d04dd0da7a20529a0315.pdf