Publication Type |
Journal Article |
School or College |
College of Engineering |
Department |
Electrical & Computer Engineering; Materials Science & Engineering |
Creator |
Stringfellow, Gerald B. |
Other Author |
Chun, Y. S.; Murata, H.; Hsu, T. C.; Ho, I. H.; Su, L. C.; Hosokawa, Y. |
Title |
Effects of V/III ratio on ordering in GaInP: atomic scale mechanisms |
Date |
1996-05-01 |
Description |
Ga0.5In0.5P layers have been grown by organometallic vapor-phase epitaxy using various values of input V/III ratio for two phosphorus precursors, phosphine, the conventional precursor, and tertiarybutylphosphine (TBP), a newly developed, less-hazardous precursor. For growth on nominally (001) GaAs substrates misoriented by 3° (and in some cases by 0° or 6°) to produce [110] steps on the surface at a growth temperature of 620 °C, the Cu-Pt-type ordering is found to be strongly affected by the input flow rate of the phosphorus precursor (V/III ratio). For decreasing input partial pressures below 3 Torr for PH3 and 0.75 Torr for TBP the low-temperature photoluminescence (PL) peak energy increases indicating a lower degree of order. This is confirmed by transmission electron diffraction results. The decrease in the degree of order corresponds to a decrease in the concentration of [1-bar 10]-oriented P dimers on the surface, as indicated by surface photoabsorption spectroscopy results. These data indicate that the reduction in ordering is caused by the loss of the (2×4) reconstructed surface during growth. The difference in the behavior for PH3 and TBP is interpreted as due to the lower pyrolysis efficiency of PH3. The surface structure measured using high-resolution atomic force microscopy indicates that the [110] steps produced by the intentional misorientation of the substrate are bunched to produce supersteps approximately 30-40 Å in height for the lowest V/III ratios. The step height decreases markedly as the input phosphorus partial pressure increases from 0.4 to 0.75 Torr for TBP and from 1 to 3 Torr for PH3. This corresponds to a change from mainly monolayer to predominantly bilayer steps in the vicinal regions between bunched supersteps. Stabilization of the bilayer steps is interpreted as due to formation of the (2×2) reconstruction on the (111)B step edges. The degree of order is an inverted U-shaped function of the flow rate of the phosphorus precursor. Thus, use of very high input V/III ratios is also found to reduce the degree of order in the Ga0.5In0.5P layers. These high input phosphorus flow rates are found to result in a monotonic increase in the density of [1-bar 10]-oriented P dimers on the surface. This decrease in order is believed to be related to a change in the structure of kinks on the [110] steps at high V/III ratios. |
Type |
Text |
Publisher |
American Institute of Physics (AIP) |
Volume |
79 |
Issue |
9 |
Subject |
Photoabsorption spectroscopy; Transmission electron diffraction; Phosphorus precursor |
Subject LCSH |
Epitaxy; Metal organic chemical vapor deposition; Order-disorder in alloys |
Language |
eng |
Bibliographic Citation |
Chun, Y. S., Murata, H., Hsu, T. C., Ho, I. H., Su, L. C., Hosokawa, Y. & Stringfellow, G. B. (1996). Effects of V/III ratio on ordering in GaInP: atomic scale mechanisms. Journal of Applied Physics, 79(9), 6900. |
Rights Management |
(c)American Institute of Physics. The following article appeared in Chun, Y. S., Murata, H., Hsu, T. C., Ho, I. H., Su, L. C., Hosokawa, Y. & Stringfellow, G. B., Journal of Applied Physics. 79(9), 1996 |
Format Medium |
application/pdf |
Format Extent |
176,355 bytes |
Identifier |
ir-main,1932 |
ARK |
ark:/87278/s6c25dqw |
Setname |
ir_uspace |
ID |
704400 |
Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6c25dqw |