Analysis of the temperature-dependent current-voltage characteristics and the barrier-height inhomogeneities of Au/GaN Schottky diodes

• Published in: Physica status solidi. A, Applications and materials science Vol. 209; no. 8; pp. 1575 - 1578
• Main Authors: Roul, Basanta, Bhat, Thirumaleshwara N., Kumar, Mahesh, Rajpalke, Mohana K., Kalghatgi, A. T., Krupanidhi, S. B.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01-08-2012; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: MBE; Normal distribution; Schottky diodes; semiconductors; Studies; Temperature; thermionic emission
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201228237

In this report, the current–voltage (I–V) characteristics of Au/GaN Schottky diodes have been carried out in the temperature range of 300–510 K. The estimated values of the Schottky‐barrier height (SBH) and the ideality factor of the diodes based on the thermionic emission (TE) mechanism were found to be temperature dependent. The barrier height was found to increase and the ideality factor to decrease with increasing temperature. The conventional Richardson plot of ln(Is/T2) versus 1/kT gives the SBH of 0.51 eV and Richardson constant value of 3.23 × 10−5 A cm−2 K−2 which is much lower than the known value of 26.4 A cm−2 K−2 for GaN. Such discrepancies of the SBH and Richardson constant value were attributed to the existence of barrier‐height inhomogeneities at the Au/GaN interface. The modified Richardson plot of ln(Is/T2)–q2σ s2/2k2T2 versus q/kT, by assuming a Gaussian distribution of barrier heights at the Au/GaN interface, provided the SBH of 1.47 eV and Richardson constant value of 38.8 A cm−2 K−2. The temperature dependence of the barrier height is interpreted on the basis of existence of the Gaussian distribution of the barrier heights due to the barrier‐height inhomogeneities at the Au/GaN interface.