Pr. Dunstan et al., The growth and electrical properties of silicon on GaAs(110) studied by scanning tunneling microscopy and scanning tunneling spectroscopy, J APPL PHYS, 86(10), 1999, pp. 5636-5641
A scanning tunneling microscope (STM) has been used to study the structural
formation of silicon overlayers deposited at room temperature on GaAs(110)
. In addition spectroscopic measurements were obtained simultaneously to re
veal electrical properties associated with the interface and overlayer form
ation. The Si coverage varied in thickness from submonolayer growth up to s
imilar to 16 monolayers. The height variations of the STM images indicate t
hat silicon islands did not exceed similar to 3 Angstrom at either submonol
ayer growth or thicker coverages. The lack of atomic resolution of the adso
rbed silicon suggests that the silicon overlayers are amorphous in nature,
confirming soft x-ray photoelectron spectroscopy (SXPS) measurements. The s
canning tunneling spectroscopy measurements clearly indicate a Fermi shift
of 0.8 eV when silicon was deposited on the clean cleaved surface of p(+) G
aAs(110). This shift is also observed on regions of the substrate which rem
ained exposed after the silicon deposition. The Fermi shifts and resultant
band bending are attributed to the formation of the Si-GaAs heterojunction
and correlation with earlier SXPS measurements prove favorable. The possibi
lities of measuring the band offsets are also considered. (C) 1999 American
Institute of Physics. [S0021-8979(99)04222-X].