Crystalline quality of ZnSe thin films grown on GaAs by pulsed laser deposition in He and Ar ambients

• Published in: Thin solid films Vol. 388; no. 1; pp. 189 - 194
• Main Authors: Ganguli, Tapas, Vedvyas, M., Bhattacharya, P., Kukreja, L.M., Ingale, Alka, Adhi, K.P., Chandrashekharan, K.S., Arora, B.M., Rustagi, K.C.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.06.2001; Elsevier Science
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Laser ablation; Laser deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Selenides; X-Ray diffraction; Zinc; Laser ablation; X-Ray diffraction; Selenides; Zinc; Inorganic compounds; Epitaxy; Transition element compounds; Controlled atmospheres; Zinc selenides; Crystal growth from vapors; Experimental study; Pulsed lasers; Crystal perfection; Characterization; Thin films; Dislocation density; II-VI semiconductors; Mismatch lattice; Heterojunctions; Laser ablation technique
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(01)00817-3

Epitaxial films of ZnSe with a thickness of approximately 1 μm, were deposited on (001) semi-insulating GaAs by pulsed laser deposition using a third harmonic Nd-YAG laser at 10 −6 torr vacuum and at various pressures of He and Ar gases. The best crystalline quality of the ZnSe epilayer was obtained when the deposition was carried out at 10 −4 torr of He. The full width at half maximum of the X-ray diffraction rocking curve of the ZnSe film deposited at 400°C in 10 −4 torr of He was approximately 230 arcsecs. A comparison of the reciprocal lattice space mappings showed that ZnSe epilayers deposited in Ar ambient have a much larger variation of lattice spacing and strain than those grown in vacuum and He ambient. The scanning electron micrographs showed that the epilayers of ZnSe deposited at 10 −4 torr of He have the least particulate density. Possible reasons for the observed improvement in the crystalline quality are discussed.