Dielectric Properties of Au/SrTiO3/p-Si Structure Obtained by RF Magnetron Sputtering in a Wide Frequency Range

Dielectric properties of Au/p-Si structure with Strontium titanate (SrTiO3) interlayer were examined in the frequency range of 100-900 kHz (by step 100 kHz). SrTiO3 thin film was deposited on p-type Si substrate using radio frequency (RF) magnetron sputtering method at a substrate temperature of 500 degrees C. Dielectric parameters such as dielectric constant (epsilon(')), dielectric loss (epsilon('')), real modulus (M-'), imaginary modulus (M-''), and electrical conductivity (sigma(ac)) of the Au/SrTiO3/p-Si structure were calculated by evaluating the results obtained from admittance spectroscopy in the frequency range of 100-900 kHz by step 100 kHz. According to the obtained results, epsilon(') values take negative values as a result of depending on frequency measurements

THE GROWTH OF InxGa1-xAs / GaAs MULTI QUANTUM WELL STRUCTURE WİTH MBE TECHNIQUE: THE INVESTIGATION OF THE STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTİES

Bu çalışmada Semicon VG80H Moleküler Demet Epitaksi sistemi kullanılarak InxGa1-xAs/GaAs çoklu kuantum kuyu yapısı büyütüldü. Büyütülen bu yapının yapısal analizi X-ışını kırınımı yöntemi kullanılarak yapıldı. Elde edilen Rocking eğrileri malzemede yer alan çoklu tabakaların ara yüzey pürüzlülüğünün az olduğunu ve tabakaların homojen olarak büyütüldüğü gözlendi. Yapının sıcaklığa bağlı optiksel analizi Fotolüminesans yöntemi ile yapıldı. Oda sıcaklığında yapılan ölçümlerden malzemenin yasak bant aralığı ve In kompozisyon oranı tayin edildi. Düşük sıcaklık ölçümlerinden ise pik enerjisi, aktivasyon enerjisi ve pik yarı genişliği hesabı yapıldı. Büyütülen çoklu kuantum kuyu yapısının elektriksel karakteristiklerinin incelenebilmesi için Au kontaklar yapıldı ve sıcaklık bağımlı (80-295 K) akım-gerilim özellikleri incelenmiştir. Yapılan analizler sonucunda, idealite faktörünün sıcaklıkla azalırken sıfır-beslem engel yüksekliğinin sıcaklıkla arttığı gözlemlendi.In this work InxGa1-xAs/GaAs multi quantum well structure was grown by Semicon VG80H Molecular Beam Epitaxy system. The structural analysis was performed by X-ray diffraction method. The obtained Rocking curves shows that the the multi layer interface smoothess are small and the growth epilayers have enough thickness and homogeneity. The temperature dependent optical analyses were performed by photoluminescence method. The forbidden band gap and the In composition was obtained from room temperature optical measurements and the peak energy, activation energy and the full width at half maximum values were obtained from temperature dependent optical measurements. For the electrical analysis of the multi quantum well structure, Au Schottky contacts were formed and the current-voltage measurements were taken in the wide temperature range (80-295 K). According to the electrical analysis, the decrease in the ideality factor and the increase in the zero-bias barrier height with temperature was observed

Modeling and Experimental Analysis of Photovoltaic Parameters of GaInP/GaAs Dual Junction p-i-n Solar Cell

In this study, the modeling and experimental analysis of photovoltaic parameters of the GaInP/GaAs dual-junction (DJ) p-i-n solar cell structure were examined. The design of the GaInP/GaAs DJ p- i-n solar cell structure was done with the drift-diffusion model (DDM), and this structure was grown with the molecular beam epitaxy (MBE) system. The fundamental parameters (open-circuit voltage (V-OC), short-circuit current density (J(SC)), fill factor (FF), and energy conversion efficiency (eta)) of these structures were determined by both modeling and the current-voltage experimental measurements. All electrical output parameters of the GaInP/GaAs DJ p-i-n solar cells obtained from modeling and experimental were compared. An increase in solar cell efficiency was observed with the integration of the i-layer

The Effects of Concentrated System on The Electrical Parameters Of GaInP/GaAs Solar Cell

III-V concentrator solar cells are suitable materials in order to reduce the cost of photovoltaic electricity. By using Fresnel lens in concentrating photovoltaic technology is an effective way to entirely use the sunlight. In the present study, the research on the efficiency analysis of the GaInP/GaAs concentrated solar cell stnicture with AlGaAs tunnel junction was performed. The electrical output parameters of this structure were determined by concentrated system with Fresnel lens. The current-voltage measurements of concentrated solar cell were carried out at room temperature under both dark and air mass 1.5 global radiations. The parameters of GaInP/GaAs concentrated solar cell at 1 Sun and at 32 Suns are compared. It is obtained that the integration of the concentrated system on the solar cell structure improves the device performance by approximate to 7.5%

Analysis of the Temperature Dependence of the Capacitance-Voltage and Conductance-Voltage Characteristics of Au/TiO2(rutile)/n-Si Structures

The capacitance-voltage-temperature (C-V-T) and the conductance/angular frequency-voltage-temperature (G/omega-V-T) characteristics of Au/TiO2(rutile)/n-Si Schottky barrier diodes (SBDs) were investigated over the temperature range from 200 K to 380 K by considering the series resistance effect. Titanium dioxide (TiO2) was deposited on n-type silicon (Si) substrate using a direct-current (DC) magnetron sputtering system at 200A degrees C. To improve the crystal quality, the deposited film was annealed at 900A degrees C to promote a phase transition from the amorphous to rutile phase. The C (-2) versus V plots gave a straight line in the reverse-bias region. The main electrical parameters, such as the doping concentration (N (D)), Fermi energy level (E (F)), depletion layer width (W (D)), barrier height (N" (CV)), and series resistance (R (S)), of Au/TiO2(rutile)/n-Si SBDs were calculated from the C-V-T and the G/omega-V-T characteristics. The obtained results show that N" (CV), R (S), and W (D) values decrease, while E (F) and N (D) values increase, with increasing temperature