DFT studies for optoelectronic properties of pure l-alanine and doped with Li

• Published in: Journal of materials science. Materials in electronics Vol. 27; no. 5; pp. 4887 - 4897
• Main Authors: Rahnamaye Aliabad, H. A., Mojarradi, Z., Yalcin, Battal G.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2016; Springer Nature B.V
• Subjects: Band theory; Characterization and Evaluation of Materials; Chemistry and Materials Science; Density functional theory; Energy gaps (solid state); Gaussian; Lithium; Materials Science; Mathematical analysis; Optical and Electronic Materials; Optoelectronics; Photonic band gaps; Dielectric Function; Lithium Atom; Electron Energy Loss Spectroscopy; Optoelectronic Property; Acidic Site
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-016-4372-1

Structural and optoelectronic properties of the pure l -alanine (CH 3 CHNH 2 COOH) and substituted with Li in two different sites CH 3 CHNHLiCOOH (basic) and CH 3 CHNH 2 COOLi (acidic) are systematically investigated by the density functional theory (DFT). We have used WIEN2k and Gaussian 09W codes for structural optimization. The optimized lattice constants are found to be consistent with the experimental results. l -Alanine is a wide indirect band gap compound and hence is an attractive material for optoelectronic applications. The calculated fundamental band gaps for CH 3 CHNH 2 COOH, CH 3 CHNHLiCOOH and CH 3 CHNH 2 COOLi are found to be 4.85, 3.50 and 2.40 eV, respectively. Obtained band gap value of 4.85 eV for l -alanine is in coincidence with the experimental (4.67 eV) and theoretical results (4.54 and 5.07 eV). Substitution of Li with H element in COOH chain, the transition from an indirect to direct band gap has been observed in sample. Optical properties such as dielectric functions and energy loss functions are also evaluated and discussed in detail.