The effect of Se doping on spectroscopic and electrical properties of GeTe

• Published in: Thin solid films 2014-01, Vol.550, p.569-574
• Main Authors: Vinod, E.M., Sangunni, K.S.
• Format: Article
• Language: English
• Subjects: Alloys; Bonding; Composition and phase identification; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Disorders; Doping; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Phase change memory; Physics; Raman spectroscopy; Surface and interface electron states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Tuning; X-ray photoelectron spectroscopy; X-rays; XPS; XRD
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.11.038

Selenium doped thin films of GeTe alloys were investigated for their structural modifications by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, X-ray photoelectron Spectroscopy (XPS) and Raman Spectroscopy. The band gap increase from 0.69 to 1.10eV with increasing Se addition signifies the possibility of band gap tuning in the material. Disorder decreases, band widens and conductivity saturates about 0.20at.% of Se addition. Structural changes are explained by the bond theory of solids. The as-deposited films are amorphous and 0.50at.% Se alloy forms a homogeneous amorphous phase with a mixture of GeSe and TeSe bonds. The XPS core level spectra and Raman spectra investigation clearly indicate the formation of GeSe, GeTe2 and TeSe bonds with Se addition. Crystallization temperature is found to be increasing with Se and the 0.10at.% Se alloy is found to have a higher resistance contrast compared to other Se concentration alloys. Up to 0.10at.% of Se addition can enhance GeTe phase change memory properties. •Se addition increases the band gap of GeTe from 0.69 to 1.10eV.•0.10at.% Se addition to GeTe shows a higher resistance contrast.•Disorder found decreases with Se addition.•Bonding changes from GeTe, GeTe2, GeSe and TeSe with increasing Se addition.•Se inhibits the GeTe crystallite growth and may occupy the interstitials.