Surface morphology and electronic structure of Ge/Si(111) 7 x 7 system

A Ge film similar to6 ml thick was grown on (7 x 7) reconstructed Si(1 1 1) substrate at room temperature as well as at elevated substrate temperature , viz. 450 and 550 degreesC. The changes in electronic structure were studi ed in situ by photoelectron spectroscopy using synchrotron radiation as wel l as helium lamp. The surface morphology was studied ex situ by using atomi c force microscopy. The growth of Ge on Si(1 1 1) 7 x 7 was found to be hig hly disordered at room temperature. At 450 degreesC, it showed columnar gro wth of Ge, with a peculiar double column structure. The increase in the tem perature from 450 to 550 degreesC changes the structure and composition of islands. At 550 degreesC, triangular pyramid shaped islands of uniform size are formed. (C) 2001 Elsevier Science B.V. All rights reserved.