STM study of pulsed laser assisted growth of Ge quantum dot on Si(1 0 0)-(2 × 1)

¹ Department of Physics, Old Dominion University, Norfolk, 23529 VA, USA
² Department of Electrical and Computer Engineering and the Applied Research Center, Old Dominion University, Norfolk, 23529 VA, USA

^a e-mail: helsayed@odu.edu

Received: 3 June 2013
Revised: 13 November 2013
Accepted: 16 December 2013
Published online: 3 February 2014

Abstract

Ge quantum dot formation on Si(1 0 0)-(2 × 1) by nanosecond pulsed laser deposition under laser excitation was investigated. Scanning tunneling microscopy was used to probe the growth mode and morphology. Excitation was performed during deposition using laser energy density of 25–100 mJ/cm². Faceted islands were achieved at a substrate temperature of ∼250 °C only when using laser excitation. The island morphology changes with increased laser excitation energy density although the faceting of the individual islands remains the same. The size of the major length of islands increases with the excitation laser energy density. A purely electronic mechanism of enhanced surface diffusion of the Ge adatoms is proposed.