Nima Naderi
Materials and Energy Research Center
[ 1 ] - Band-Gap Tuning Of Electron Beam Evaporated Cds Thin Films
The effect of evaporation rate on structural, morphological and optical properties of electron beam evaporated CdS thin films have been investigated. CdS thin film deposited by electron beam evaporation method in 12nm/min and 60nm/min evaporation rates on glass substrates. X-ray diffraction, scanning electron microscopy, UV-Vis-NIR spectroscopy and Atomic Force Microscopy were used to character...
[ 2 ] - بهینه سازی رشد نانومیله های یکنواختZnO بر روی بستر سیلیکون بذردار به روش رسوب حمام شیمیایی
نانومیله های اکسیدروی به روش رسوب حمام شیمیایی (CBD) روی بستر سیلیکون بذردار به صورت عمودی و یکنواخت رشد داده شدند. از لایه نازک اکسیدروی که به روش کندوپاش بر روی بستر سیلیکونی لایه نشانی شد به عنوان لایه بذر استفاده شد. اثرات دما و زمان رشد بر خواص ساختاری و مورفولوژیکی نانومیله های اکسید روی با استفاده از میکروسکوپ الکترونی روبشی و پراش اشعه ایکس بررسی شد. مطالعات انجام شده نشان داد که است...
[ 3 ] - سنتز و بررسی خواص الکترواپتیکی سیلیکون متخلخل به روش ترکیبی شیمیایی و الکتروشیمیایی
در این تحقیق، سیلیکون متخلخل به روش نوین حکاکی ترکیبی شیمیایی و الکتروشیمیایی سنتز شد و تغییرات خواص اپتیکی و ساختاری بر اساس درجه تخلخل نمونه ها مورد بررسی قرار گرفت. در این روش سطح زیر لایه های سیلیکونی ابتدا توسط روش اچینگ شیمیایی به مدت Td (زمان تاخیر) آماده سازی گردید. سپس در روش اچینگ الکتروشیمیایی حفره‌های اولیه تولید شده در مرحله قبل، امتداد یافته و سیلیکون متخلخل یکنواختی ای...
[ 4 ] - بررسی تاثیر غلظت فسفر بر عملکرد سلولهای خورشیدی حالت جامد پایه سیلیکون متخلخل
در پژوهش حاضر، تاثیر غلظت فسفر در محلول آلاینده بر عملکرد سلولهای خورشیدی حالت جامد پایه سیلیکون متخلخل مورد بررسی قرار گرفت. برای این منظور بسترهای سیلیکونی به روش حکاکی شیمیایی توسط نقره و با استفاده از محلول حکاکی آبی حاوی هیدروفلوریک اسید و هیدروژنپروکسید به نسبتهای 82/0، 87/0 و 89/0 حکاکی شدند و خصوصیات نوری و سطحی آنها به ترتیب توسط بازتابسنجی و میکروسکوپهای نوری و الکترونی روب...
[ 5 ] - Effect of the Sulfur Concentration on the Optical Band Gap Energy and Urbach Tail of Spray-Deposited ZnS Films
Zinc sulfide (ZnS) films were deposited through a simple and low cost spray pyrolytic technique using mixed aqueous solutions of zinc nitrate and thiourea. The structural and optical properties of these films were investigated as a function of initial (Zn:S) molar ratio in the precursor solution, which varied between (1:1) and (1:3). X-ray diffraction (XRD) analysis revealed that wurtzite...
[ 6 ] - Optimization of Chemical Texturing of Silicon Wafers Using Different Concentrations of Sodium Hydroxide in Etching Solution
In this paper, the morphology of chemically etched silicon with various concentration is reported. The surface of Silicon (100) has pyramidal structures which can be used for anti-reflection applications in solar cells. Pyramidal structures can capture incident sun light therefore can enhance the efficiency of silicon solar cells. The structure of silicon pyramid was studied using scanni...
[ 7 ] - Nb2O5 Nanoparticles Synthesis by Chemical Surfactant-Free Methods: ltrasonic Assisted Approach
In this study, spherical Nb2O5 nanoparticles were synthesized by a novel chemical method as a simple, robust, surfactant-free, non-toxic and widely applicable approach. In order to investigate the effect of initial concentration on particle sizes, nanoparticles with different initial concentration were synthesized. Ultrasonic assisted method was applied and the effects of ultrasonic treat...
[ 8 ] - Investigation of HF/H2O2 Concentration Effect on Structural and Antireflection Properties of Porous Silicon Prepared by Metal-Assisted Chemical Etching Process for Photovoltaic Applications
Porous silicon was successfully prepared using metal-assisted chemical etching method. The Effect of HF/H2O2 concentration in etching solution as an affecting parameter on the prepared porosity type and size was investigated. Field emission electron microscopy (FE-SEM) confirmed that all etched samples had porous structure and the sample which was immersed into HF/H2O2 withmolar ratio of 7/3.53...
[ 9 ] - Correlation Between Surface Morphology and Optical Properties of Quasi-Columnar Porous Silicon Nanostructures
In the current work, the effect of surface morphology on light emission property and absorption behavior of quasi-columnar macro-porous silicon (PS) was investigated. PS structures with different morphology were synthesized using photo-electrochemical etching method by applying different etching current densities. SEM micrographs showed that empty macro-pores size and porosity of PS layers were...
[ 10 ] - Investigation of Physical Properties of e-Beam Evaporated CdTe Thin Films for Photovoltaic Application
CdTe thin films with 2.8 µm thickness were deposited by electron beam evaporation method. X-ray diffraction, scanning electron microscopy, UV-Vis-NIR spectroscopy and atomic force microscopy (AFM) were used to characterize the films. The results of AFM analysis revealed that the CdTe films have uniform surface. CdTe thin films were heat-treated by SnCl2 solution. Structural analysis using XRD s...
[ 11 ] - Effect of growth time on ZnO thin films prepared by low temperature chemical bath deposition on PS substrate
ZnO thin films were successfully synthesized on a porous silicon (PS) substrate by chemical bathdeposition method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM),and photoluminescence (PL) analyses were carried out to investigate the effect of growth duration(3, 4, 5, and 6 h) on the optical and structural properties of the aligned ZnO nanorods. T...
[ 12 ] - Ultraviolet detectors based on annealed zinc oxide thin films: epitaxial growth and physical characterizations
In this report, ultraviolet (UV) detectors were fabricated based on zinc oxide thin films. The epitaxial growth of zinc oxide thin films was carried out on bare glass substrate with preferred orientation to (002) plane of wurtzite structure through radio frequency sputtering technique. The structural properties indicated a dominant peak at 2θ=34.28º which was matched with JCPDS reference card N...