On the mechanism of current-transport in Cu/CdS/SnO2/In-Ga structures


Uslu H., ALTINDAL Ş., POLAT İ., Bayrak H., BACAKSIZ E.

JOURNAL OF ALLOYS AND COMPOUNDS, cilt.509, sa.18, ss.5555-5561, 2011 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 509 Sayı: 18
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1016/j.jallcom.2011.02.033
  • Dergi Adı: JOURNAL OF ALLOYS AND COMPOUNDS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.5555-5561
  • Anahtar Kelimeler: Cu/CdS/SnO2/In-Ga structures, Current-transport mechanisms, Tunneling, Temperature dependence, Series resistance, CURRENT-VOLTAGE CHARACTERISTICS, CDS THIN-FILMS, BIAS I-V, ELECTRICAL CHARACTERISTICS, CARRIER TRANSPORT, INTERFACE STATES, CHARGE-TRANSPORT, SCHOTTKY DIODES, C-V, TEMPERATURE
  • Gazi Üniversitesi Adresli: Evet

Özet

The structural and optical properties of CdS films deposited by evaporation were investigated. X-ray diffraction study showed that CdS films were polycrystalline in nature with zinc-blende structure and a strong (1 1 1) texture. The study has been made on the behavior of Cu/n-CdS thin film junction on SnO2 coated glass substrate grown using thermal evaporation method. The forward bias current-voltage (I-V) characteristics of Cu/CdS/SnO2/In-Ga structures have been investigated in the temperature range of 130-325 K. The semi-logarithmic lnI-V characteristics based on the Thermionic emission (TE) mechanism showed a decrease in the ideality factor (n) and an increase in the zero-bias barrier height (Phi(Bo)) with the increasing temperature. The values of n and Phi(Bo) change from 8.98 and 0.29 eV (at 130 K) to 3.42 and 0.72 eV (at 325 K), respectively. The conventional Richardson plot of the ln(I-o/T-2) vs q/kT shows nonlinear behavior. The forward bias current I is found to be proportional to I-o(T) exp(AV), where A is the slope of ln(I)-V plot and almost independent of the applied bias voltage and temperature, and I-o(T) is relatively a weak function of temperature. These results indicate that the mechanism of charge transport in the SnO2/CdS/Cu structure in the whole temperature range is performed by tunneling among interface states/traps or dislocations intersecting the space-charge region. In addition, voltage dependent values of resistance (R-(i) under bar) were obtained from forward and reverse bias I-V characteristics by using Ohm's law for each temperature level. (C) 2011 Elsevier B.V. All rights reserved.