Effects of V/III ratio on ordering in GaInP: Atomic scale mechanisms

Journal Article · Wed May 01 04:00:00 EDT 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.361513· OSTI ID:283552

Chun, Y S; Murata, H; Hsu, T C; Ho, I H; Su, L C; Hosokawa, Y; Stringfellow, G B ^[1]

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1. College of Engineering, University of Utah, Salt Lake City, Utah 84112 (United States)

Ga{sub 0.5}In{sub 0.5}P 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{degree} (and in some cases by 0{degree} or 6{degree}) 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 PH{sub 3} 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 [{bar 1}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{times}4) reconstructed surface during growth. The difference in the behavior for PH{sub 3} and TBP is interpreted as due to the lower pyrolysis efficiency of PH{sub 3}. 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{endash}40 A 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 PH{sub 3}. 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{times}2) reconstruction on the (111){ital B} step edges. (Abstract Truncated)

• OSTI ID: 283552
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
DIMERS
ELECTRON DIFFRACTION
GALLIUM PHOSPHIDES
INDIUM PHOSPHIDES
LAYERS
MICROSCOPY
ORDER PARAMETERS
PHOTOLUMINESCENCE
PRECURSOR
STRUCTURAL CHEMICAL ANALYSIS
SURFACE PROPERTIES
SURFACE STRUCTURE
VAPOR PHASE EPITAXY