Influence of temperature on Al/p-CuInAlSe2 thin-film Schottky diodes

Al/p-CuInAlSe 2 Schottky diodes were fabricated using the optimized thin layers of CuInAlSe 2 semiconductor. These diodes were used to study their temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) analysis over a wide range of 233–353 K. Based on these measurements, diode parameters such as ideality factor ( η ), barrier height (ϕ bo ) and series resistance ( R s ) were determined from the downward curvature of I–V characteristics using Cheung and Cheung method. The extracted parameters were found to be strongly temperature dependent; ϕ bo increases, while η and R s decrease with increasing temperature. This behavior of ϕ bo and η with change in temperature has been explained on the basis of barrier inhomogeneities over the MS interface by assuming a Gaussian distribution (GD) of the ϕ bo at the interface. GD of barrier height (BH) was confirmed from apparent BH (ϕ ap ) versus q /2 kT plot, and the values of the mean BH and standard deviation (σ s ) obtained from this plot at zero bias were found to be 1.02 and 0.14 eV, respectively. Also, a modified ln J s / T 2 - q 2 σ s 2 / 2 k 2 T 2 versus q / kT plot for Al/p-CuInAlSe 2 Schottky diodes according to the GD gives ϕ bo and Richardson constant ( A ** ) as 1.01 eV and 26 Acm −2 K −2 , respectively. The Richardson constant value of 26 Acm −2 K −2 is very close to the theoretical value of 30 Acm −2 K −2 . The discrepancy between BHs obtained from I–V and C–V measurements has also been interpreted.