Arama Sonuçları

Listeleniyor 1 - 8 / 8
  • Öğe
    Electrical characteristics of the Al/Congo Red (CR)/p-Si semiconductor diodes
    (Dumlupınar Üniversitesi, 2015-05) Güllü, Ömer; Pakma, Osman; Turut, Abdulmecit; Arsel, İsmail
    In this work, we have studied the electrical characteristics of the Al/CR/p-Si MIS Schottky structures formed by coating of the organic material directly on p-Si substrate. It has been seen that the CR thin film on the p-Si substrate has indicated a good rectifying behavior. The barrier height and the ideality factor of the device have been calculated from the I-V characteristic. We have also studied the suitability and possibility of the MIS diodes for use in barrier modification of Si MS diodes. In addition, we have compared the parameters of the Al/CR/p-Si MIS Schottky diodes with those of conventional Al/p-Si MS diodes. We have observed that the b value of 0.77 eV obtained for the Al/CR/p-Si device was significantly larger than BH value of the conventional Al/p-Si MS contact. Thus, the modification of the interfacial potential barrier for metal/Si diodes has been achieved by using the CR organic interlayer. This was attributed to the fact that the CR interlayer increased the effective b by influencing the space charge region of Si. The interface-state density of the MIS diode was found to vary from 1.24×1013 eV-1 cm-2 to 2.44×1012 eV-1 cm-2.
  • Öğe
    A study of the rectifying behaviour of aniline green-based Schottky diode
    (Elsevier, 2010-02) Güllü, Ömer; Aydoğan, Şakir
    An Al/aniline green (AG)/Ga2Te3 device was fabricated and the current–voltage (I–V), capacitance–voltage (C–V) and capacitance–frequency (C–f) characteristics of the device have been investigated at room temperature. The values of the ideality factor, series resistance and barrier height obtained from Cheung and Norde methods were compared, and it was seen that there was an agreement with each other. It was seen that the forward bias current–voltage characteristics at sufficiently large voltages has shown the effect of the series resistance. In addition, it was seen from the C–f characteristics that the values of capacitance have been decreased towards to the high frequencies. The higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the Ga2Te3 that can follow the ac signal.
  • Öğe
    Electronic properties of Al/DNA/p-Si MIS diode: Application as temperature sensor
    (Elsevier, 2011-01) Güllü, Ömer; Türüt, Abdülmecit
    The current-voltage (I-V) measurements were performed in the temperature range (200-300 K) on Al/DNA/p-Si Schottky barrier type diodes. The Schottky diode shows non-ideal I-V behaviour with ideality factors n equal to 1.34 ± 0.02 and 1.70 ± 0.02 at 300 K and 200 K, respectively, and is thought to have a metal-interface layer-semiconductor (MIS) configuration. The zero-bias barrier height Φb determined from the I-V measurements was 0.75 ± 0.01 eV at 300 K and decreases to 0.61 ± 0.01 eV at 200 K. The forward voltage-temperature (VF-T) characteristics were obtained from the I-V measurements in the temperature range 200-300 K at different activation currents (IF) in the range 20 nA-6 μA. The VF-T characteristics were linear for three activation currents in the diode. From the VF-T characteristics at 20 nA, 100 nA and 6 μA, the values of the temperature coefficients of the forward bias voltage (dV F/dT) for the diode were determined as -2.30 mV K-1, -2.60 mV K-1 and -3.26 mV K-1 with a standard error of 0.05 mV K-1, respectively.
  • Öğe
    Electrical characterization of the Al/new fuchsin/n-Si organic-modified device
    (Elsevier, 2010-03) Güllü, Ömer; Asubay, Sezai; Turut, Abdulmecit; Aydoğan, Şakir
    The current–voltage (I–V) and the capacitance–voltage (C–V) characteristics of the Al/new fuchsin (NF)/n-Si device have been investigated at room temperature. The I–V characteristic of the device shows a good rectification. The ideality factor and the barrier height from the I–V characteristics have been determined as 3.14 and 0.80 eV, respectively. A modified Norde's function combined with the conventional I–V method has been used to extract the parameters including the barrier height and the series resistance. The barrier height and the series resistance obtained from Norde's function have been compared with those from Cheung functions, and it has been seen that there was a good agreement between those from both method. It has also been seen that the values of diode capacitance increased up to the constant values for the forward bias.
  • Öğe
    The analysis of lateral distribution of barrier height in identically prepared Co/n-Si Schottky diodes
    (Elsevier, 2009-11-03) Güllü, Ömer; Karataş, Şükrü; Güler, Gülşen; Bakkaloğlu, Ömer Faruk
    We have studied the experimental linear relationship between ideality factors and barrier heights (BHs) for Co/n-Si metal–semiconductor (MS) structures with a doping density of about 1015 cm−3. The barrier heights for the Co/n-type Si metal–semiconductor structures from the current–voltage (I–V) characteristics varied from 0.64 to 0.70 eV, the ideality factor n varied from 1.18 to 1.26, and from reverse bias capacitance–voltage (C−2–V) characteristics the barrier height varied from 0.68 to 0.81 eV. The experimental barrier height distributions obtained from the I–V and C−2–V characteristics were fitted by a Gaussian distribution function, and their mean values were found to be 0.67 and 0.75 eV, respectively. Furthermore, the lateral homogeneous BH value of approximately 0.81 eV for Co/n-Si metal–semiconductor structures was obtained from the linear relationship between experimental effective BHs and ideality factors.
  • Öğe
    Ultrahigh (100%) barrier modification of n-InP Schottky diode by DNA biopolymer nanofilms
    (Elsevier, 2010-04) Güllü, Ömer
    Here I demonstrate that DNA biopolymer molecules can control the electrical characteristics of conventional Al/n-InP metal–semiconductor contacts. Results show that DNA increases an effective barrier height as high as 0.87 eV by influencing the space charge region of n-InP device with a good rectifying behavior
  • Öğe
    Organik arayüzey tabakalı Al/CuPc /p-InP kontakların fabrikasyonu ve elektriksel parametrelerinin incelenmesi
    (Batman Üniversitesi, 2015-07-01) Aslan, Filiz; Güllü, Ömer; Ocak, Yusuf Selim; Rüzgar, Şerif; Tombak, Ahmet; Özaydın, Cihat; Pakma, Osman; Arsel, İsmail
    Bu çalışmada termal buharlaştırma metodu kullanılarak bakır fitalosiyanin (CuPc) p-InP kristali üzerine kaplandı. Yine termal buharlaştırma sistemi kullanılarak oluşan ince organik film üzerine vakum ortamında alüminyum metali kaplandı ve Al/CuPc/p-InP diyot yapısı oluşturuldu. Al/CuPc/p-InP diyotunun oda sıcaklığında, karanlık ve aydınlık ortamda akım-gerilim (I-V) ölçümleri alındı. I-V grafiğinden bu yapının doğrultucu özellik gösterdiği görüldü. Aydınlık ortamda yapılan ölçümler 100 mW/cm2 ışık şiddeti altında yapıldı ve bu ölçümler doğrultusunda diyotun fotodiyot özellik gösterdiği görüldü. Ayrıca farklı yöntemlerle Al/CuPc/p-InP Schottky diyotunun karakteristik parametreleri ( idealite faktörü (n) ,engel yüksekliği (Φb) ve seri direnç (Rs) ) hesaplandı.
  • Öğe
    High barrier Schottky diode with organic interlayer
    (Elsevier, 2012-03) Güllü, Ömer; Aydoğan, Şakir; Türüt, Abdülmecit
    A new Cu/n-InP Schottky junction with organic dye (PSP) interlayer has been formed by using a solution cast process. An effective barrier height as high as 0.82 eV has been achieved for Cu/PSP/n-InP Schottky diodes, which have good currentvoltage (IV) characteristics. This good performance is attributed to the effect of formation of interfacial organic thin layer between Cu and n-InP. By using capacitancevoltage measurement of the Cu/PSP/n-InP Schottky diode the diffusion potential and the barrier height have been calculated as 0.73 V and 0.86 eV, respectively. From the IV measurement of the diode under illumination, short circuit current (I sc) and open circuit voltage (V oc) have been extracted as 0.33 μA and 150 mV, respectively.