Sl. Zuo et al., ATOMIC-SCALE COMPOSITIONAL STRUCTURE OF INASP INP AND INNASP/INP HETEROSTRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY/, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 16(4), 1998, pp. 2395-2398
Cross-sectional scanning tunneling microscopy (STM) has been used to c
haracterize the atomic-scale structure of InAs0.35P0.65/InP and InN0.0
1As0.35P0.64/InP strained-layer multiple quantum well structures grown
by gas-source molecular-beam epitaxy. Atomically resolved STM images
of the (110) cross-sectional plane reveal nanoscale clustering within
the InAsxP1-x alloy layers, with the boundaries between As-rich and P-
rich regions in the alloy layers appearing to be preferentially orient
ed along the [(1) over bar 12] and [1 (1) over bar 2] directions in th
e (110) plane. (1 (1) over bar 0) cross-sectional images reveal that c
onsiderably less compositional variation appears within the (1 (1) ove
r bar 0) plane; features elongated along the [110] direction are obser
ved, but few [112] boundaries are seen. These observations suggest tha
t the boundaries between As-rich and P-rich clusters may form preferen
tially within the (1 (1) over bar 1) and ((1) over bar 11) planes. Com
parisons of filled-state images of InAsxP1-x/InP and InNxAsyP1-x-y/InP
heterostructures suggest that N incorporation increases the valence-b
and offset in InNxAsyP1-x-y/InP compared to that in InAsxP1-x/InP. (C)
1998 American Vacuum Society.