The behavior of the I-V-T characteristics of inhomogeneous (Ni/Au)-Al0.3Ga0.7N/AlN/GaN heterostructures at high temperatures
Please cite this item using this persistent URLhttp://hdl.handle.net/11693/13407
European Physical Journal: Applied Physics
Published ashttp://dx.doi.org/ 10.1063/1.2777881
- Department of Physics 
American Institute of Physics.
We investigated the behavior of the forward bias current-voltage-temperature (I-V-T) characteristics of inhomogeneous (Ni/Au)-Al0.3Ga0.7N/AlN/GaN heterostructures in the temperature range of 295-415 K. The experimental results show that all forward bias semilogarithmic I-V curves for the different temperatures have a nearly common cross point at a certain bias voltage, even with finite series resistance. At this cross point, the sample current is temperature independent. We also found that the values of series resistance (R-s) that were obtained from Cheung's method are strongly dependent on temperature and the values abnormally increased with increasing temperature. Moreover, the ideality factor (n), zero-bias barrier height (Phi(B0)) obtained from I-V curves, and R-s were found to be strongly temperature dependent and while Phi(B0) increases, n decreases with increasing temperature. Such behavior of Phi(B0) and n is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution (GD) of the barrier heights (BHs) at the metal/semiconductor interface. We attempted to draw a Phi(B0) versus q/2kT plot in order to obtain evidence of the GD of BHs, and the values of (Phi) over bar (B0)=1.63 eV and sigma(0)=0.217 V for the mean barrier height and standard deviation at a zero bias, respectively, were obtained from this plot. Therefore, a modified ln(I-0/T-2)-q(2)sigma(2)(0)/2(kT)(2) versus q/kT plot gives Phi(B0) and Richardson constant A(*) as 1.64 eV and 34.25 A/cm(2) K-2, respectively, without using the temperature coefficient of the barrier height. The Richardson constant value of 34.25 A/cm(2) K-2 is very close to the theoretical value of 33.74 A/cm(2) K-2 for undoped Al0,3Ga0,7N. Therefore, it has been concluded that the temperature dependence of the forward I-V characteristics of the (Ni/Au)-Al0.3Ga0.7/AlN/GaN heterostructures can be successfully explained based on the thermionic emission mechanism with the GD of BHs. (c) 2007 American Institute of Physics.
Tekeli, Z., Altindal, S., Çakmak, M., Ozcelik, S., Caliskan, D., & Ozbay, E. (2007). The behavior of the IVT characteristics of inhomogeneous (Ni/Au)-Al~ 0~.~ 3Ga~ 0~.~ 7N/AlN/GaN heterostructures at high temperatures. Journal of Applied Physics, 102(5), 054510.