Electrical properties of Ir/n-InGaN/Ti/Al Schottky barrier diode in a wide temperature range

R. Padma, V. Rajagopal Reddy*

Department of Physics, Sri Venkateswara University, Tirupati 517 502, India  

Adv. Mater. Lett., 2014, 5 (1), pp 31-38

DOI: 10.5185/amlett.2013.6503

Publication Date (Web): Dec 28, 2013

E-mail: reddy_vrg@rediffmail.com

Abstract


The temperature dependent current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Ir/n-InGaN Schottky contacts have been investigated and analysed in the temperature range of 100-400 K. The estimated barrier heights and ideality factor of Ir/n-InGaN Schottky diode are 0.30 eV (I-V), 1.15 eV (C-V) and 3.05 at 100 K, and 0.94 eV (I-V), 0.97 eV (C-V) and 1.20 at 400 K respectively. The barrier height (Φb), ideality factor (n) and series resistance (RS) of Ir/n-InGaN Schottky diode are also evaluated using Cheung’s and Norde methods. Results show that the barrier heights (I-V) increase while ideality factor and series resistance decease with increasing temperature. Further, the discrepancy between Schottky barrier heights estimated from I-V and C-V measurements is also explained. It is observed that the interface state density Nss decreases with an increasing temperature. Experimental results showed that the conduction current is dominated by Poole-Frenkel emission in the temperature range from 100 K to 340 K and by Schottky emission above 340 K. The dominate conduction mechanism changed from Poole-Frenkel to Schottky emission in the temperature range from 340 K to 370 K. Finally, it is concluded that the temperature-dependent I–V characteristics of the Ir/n-InGaN Schottky diode can be successfully explained on the basis of thermionic emission (TE) mechanism.

Keywords

Ir Schottky contact, n-type InGaN, Electrical characteristics, Schottky barrier heights, Series resistance, Poole-Frenkel and Schottky emissions.

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