Growth and characterisation of layers with composition close to crossover from direct to indirect band gap

Synchrotron topography and X-ray diffraction study of GaInP layers grown on GaAs/Ge

“…InP hillocks similar in their appearance to those typical for GaInP/GaAs layers [4][5][6][7] were also found in the GaInP layers grown on GaAs/Ge substrates. The InP hillocks had a surface density of % 2000 cm À2 , and they were observed to be very homogenous in their faceted form, crystallite orientations and size ð % 6 Â 12 mm 2 Þ.…”

“…Some differences in the shapes of the X-ray maxima arising from the asymmetric strain is observed in RSMs of Figs. 3 and 4, but due to the relatively small strain in samples A and B, the differences in peak shapes between Figs Similar hillocks in Ga 1Àx In x P=GaAs with 0:388 r x r0:552 have been reported in [6], and they are a well-known problem in GaInP epitaxy [4,5,7]. However, it is possible to grow hillock-free GaInP layers using PH 3 as P precursor, if the PH 3 flow is modulated during the MOVPE growth [17].…”

“…The GaAs/ Ge structures used as substrates in this work are of a high crystal quality and have been previously studied in [2,3]. The main idea for using the GaAs/Ge substrates is to apply prior knowledge about growing GaInP on GaAs [4][5][6][7] to Ge substrates with only minor modifications. Also, problems with anti-phase domains (APD) appearing in GaAs epilayers on Ge were already solved in a previous publication [2], and by using GaAs/Ge substrates instead of plain Ge substrate the possible problem of APD formation on GaInP/Ge interface is probably avoided.…”

Impact of growth conditions on the spatial non‐uniformities of composition in InGaP epitaxial layers

“…We found that the final layer with x In = 0.27 may be reached in 8 steps using a grading rate of 10%In/1 µm, a step width of 300 nm, and a growth temperature of T g = 740 o C. The optimization process and growth details are described elsewhere [3]. The influence of the spinodal-like decomposition of the In x Ga 1-x P was averted by an intentional increase in the V/III ratio during the growth from a starting value of 75 to the a final value of 350 [4]. In this paper, we report on the uniformity of an In x Ga 1-x P epitaxial layer (with expected x In = 0.27) grown on the top of the graded buffer.…”

Photoluminescence and TEM characterization of (AlyGa1–y)1–xInxP layers grown on graded buffers

“…The application is partially hindered by the indirect band-gap structure of GaP and InGaP with a low content of In. In the In x Ga 1-x P ternary compound, the crossover from an indirect to a direct band-gap one occurs close to the InP molar fraction of x = 0.27 [3,4]. This composition of ternary alloy (or another composition with a higher InP content, higher x value) has to be reached for the preparation of electroluminescent devices.…”