The Gaussian distribution of barrier height in Au/n-GaAs Schottky diodes at high temperatures


TATAROĞLU A. , Altindal Ş. , Pur F. Z. , Ataseven T., Sezgin S.

OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS, cilt.5, ss.438-442, 2011 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 5
  • Basım Tarihi: 2011
  • Dergi Adı: OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS
  • Sayfa Sayıları: ss.438-442

Özet

The current-voltage (I-V) characteristics of Au/n-GaAs (MS) Schottky diodes were determined in the temperature range of 300-400 K. The estimated zero-bias barrier height (Phi(Bo)) and the ideality factor (n) assuming thermionic emission (TE) theory show strong temperature dependence. The barrier height for current transport decreases and the ideality factor increases with the decrease temperatures. This behavior of Phi(Bo) and n is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution (GD) of the barrier heights (BHs) at the metal/semiconductor interface. The Richardson plot is found to be linear in the temperature range measured, but activation energy value of 0.322 eV and Richardson constant (A*) value of 4.12x10(-4) Acm(-2)K(-2) obtained this plot are much lower than the known values. The nonlinearity in the Richardson plot and strong dependence of Schottky barrier parameters on temperature may be attributed to the spatial inhomogeneity in the interface. We attempted to draw a Phi(Bo) versus q/2kT plot in order to obtain evidence of the GD of BHs, and the values of (Phi) over bar (Bo) = 0.912 eV and sigma(o) = 0.132 V for the mean barrier height and standard deviation at a zero bias, respectively, were obtained from this plot. A modified In(I-o/T-2)-q(2)sigma(2)(o)/2k(2)T(2) versus q/kT plot gives (Phi) over bar (Bo), and A* as 0.914 eV and 8.32 Acm(-2)K(-2), respectively. This value of the Richardson constant 8.32 Acm(-2)K(-2) is very close to the theoretical value of 8.16 Acm(-2)K(-2) for n-type GaAs.