Document Type : Research Article


Material Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, TN, India


AIN thin films were grown by ion beam sputter deposition in reactive assistance of N+/N2+ ions on Si (100) substrates. During deposition, assisted ion energy (EA) was varied as 90 eV and 120 eV with a post deposition exposure to N2 plasma. The resultant films were characterized by grazing incidence x-ray diffraction (GIXRD) for their structure and atomic force microscopy (AFM) for their root mean square (rms) surface roughness (δ). UV-VIS spectrophotometry was carried out to explore their optical band-gap with associated Urbach (EU) and weak absorption tail (EWAT) energies. Our results show that, AlN thin film grown with 90 eV reactive ion assistance possesses larger optical band gap (Eg) of 5.3 eV associated with comparatively narrower band tails when compared to those AlN thin film samples which were grown for 120 eV reactive ion assistance. These optical band-gaps are further correlated with corresponding Urbach energy tails which can be used as a measure of disorder in microstructure of the film. Also, appropriate optimization of energy tails substantiates the possibility of band gap engineering as per the requirement of different thin film devices. Copyright © 2017 VBRI Press.


1.Lu Y., Shelton, S., and Horsley, D. A., Solid-State Sensors.
Actuat. Microsyst. Workshop, Hilton Head, SC, USA, 2014,131.

Lu, Y., Heidari, A., Shelton, S., Guedes, A., Horsley, D. A., IEEE
27th MEMS, San Francisco,
CA, USA, 2014, 745.
Griffin, B., A., Williams, M. D., Coffman, C. S., Sheplak, M.; J.
Microelectromech. Syst., 2011, 20, 476.

Mastronardi, V. M., Guido, F., Amato, M., Vittorio, M. D.,
Petroni, S.; Microelectron. Eng., 2014, 121, 59

Lu, Y., Horsley, D. A.,; J. of Microelectromech. Syst., 2014, 27th
in Proc. IEEE 27th MEMS, USA,
2015, 1.
Ghodssi, R., Lin, P., (Eds.), MEMS Materials and Processes
Handbook; Springer: USA, 2011.

Ho, C., J., Shing, t., K., Li, P. C.; Tamkang J. of Sci. and Eng.,
2004, 7, 1.

Cappelli, E., Trucchi, D. M., Orlando, S., Valentini, V., Mezzi, A.,
, S.; Appl. Phys. A, 2014, 114, 611.
Takahashi, K., Yoshikawa, A., Sandhu, A. (Eds.), Wide Bandgap
Semiconductors: Fundamental Properties and Modern Photonic

and Electronic Devices, Springer: USA, 2007.

Sharma, N., Prabakar, K., Ilango, S., Dash, S., Tyagi, A. K.; Appl.
Surf. Sci., 2015, 347, 875

Singh, J., (Eds.), Optical Properties of Condensed Matter and
Applications, Wiley: 2006

Adachi, S., (Eds.), Optical Properties of Crystalline and
Amorphous semiconductors: Materials and Fundamental

Springer, New York, 1999.