L. Bolotov et al., Semimetal to semiconductor transition in ErP islands grown on InP(001) dueto quantum-size effects, PHYS REV B, 59(19), 1999, pp. 12236-12239
Thickness-dependent changes in the electronic states of semimetal ErP islan
ds grown on the InP(001) surface by organometallic vapor-phase epitaxy have
been investigated by means of scanning tunneling microscopy/spectroscopy.
The normalized differential conductance spectra show a semimetal behavior f
or the ErP islands (20-50 nm in size) with thickness larger than 3.4 nm, wh
ile the spectra taken for the islands thinner than 3.4 nm reveal a semicond
ucting gap varying to similar to 1 eV. The thickness dependence of the obse
rved gap is explained by the energy gap between the electron sublevel and t
he hole sublevel calculated using a one-dimensional square-well potential m
odel with infinite barriers. The results demonstrate a semimetal to semicon
ductor transition due to the quantum size effect on the semimetal ErP band
structure with a band overlap of -0.3 eV. [S0163-1829(99)01020-6].