Properties of undoped and Sb-doped CdTe surfaces prepared by conventional and photo-assisted molecular beam epitaxy

Photoassisted physical vapor epitaxial growth of semiconductors: a review of light-induced modifications to growth processes

“…One early explanation was that enhanced anion desorption under photon irradiation creates openings in the host atomic reconstruction on the epilayer surface that makes it easier for dopant atom incorporation. 11 Presumably, this indicated that Sb was more likely to incorporate into the epilayer. In ZnSe, a reduction in the growth rate under illumination due to excessive Se desorption combined with an increase in the acceptor density, measured by electrochemical profiling, was concluded to be caused specifically by an increase in N acceptors.…”

“…Irradiation of the growth surface by above-bandgap photons allowed II-VI epitaxy to proceed at lower substrate temperatures, and it was also found to improve both crystalline quality and the doping efficiency in CdTe, HgCdTe, ZnSe and ZnS. 9,10,11,12,13 Much of this work was curtailed around the same time that the intense II-VI semiconductor research of the 1980s and 1990s tapered off in favor of wide bandgap nitride development. Yet recently there has been renewed interest in photoassisted VPE as a mean to overcome new challenges associated with the synthesis of increasingly complex materials, wide bandgap semiconductors and heterostructures.…”

“…In the 1980s, a number of research groups began to apply photo-assisted epitaxy techniques to the growth of Si, III-V and especially II-VI semiconductors by OMVPE and MBE. Irradiation of the growth surface by above-bandgap photons allowed II-VI epitaxy to proceed at lower substrate temperatures, and it was also found to improve both crystalline quality and the doping efficiency in CdTe, HgCdTe, ZnSe and ZnS [9][10][11][12][13]. Much of this work was curtailed around the same time that the intense II-VI semiconductor research of the 1980s and 1990s tapered off in favor of wide bandgap nitride development.…”

“…The change in the desorption constant of cation and anion species was directly measured by Benson, et al, for the case of Cd, Sb and Te desorption from a CdTe surface during MBE growth. 11 Without photon irradiation, Te desorbed with an activation energy of 1.9 eV, while Cd desorbed with an activation energy of 5.1 eV (see Fig. 3a).…”

“…9,10,11,12,13 Much of this work was curtailed around the same time that the intense II-VI semiconductor research of the 1980s and 1990s tapered off in favor of wide bandgap nitride development. Yet recently there has been renewed interest in photoassisted VPE as a mean to overcome new challenges associated with the synthesis of increasingly complex materials, wide bandgap semiconductors and heterostructures.…”