Investigation of graded InxGa1-xP buffer by Raman scattering method

Abstract The compositional changes of InxGa1−xP graded buffer inserted between GaP substrate and subsequently grown In0.36Ga0.64P homojunction LED structure were investigated by Raman spectroscopy. The indium content of InxGa1−xP interlayers was increased in eight steps with thickness of 300 nm and constant compositional change ΔxIn between the steps. The properties of InxGa1−xP graded buffer along the structure cross-section have been studied by Raman back scattering method and the changes in GaP LO and TO phonons were investigated. Raman shift of 13 cm−1 in GaP-like LO1 phonon was measured on beveled [ 100 ] surface for compositional change of InxGa1−xP layer in the range of 0 [ 011 ] direction revealed a strong TO phonon at 366 cm−1 and weak LO phonon peak at 405 cm−1 in GaP substrate. By reaching the graded InxGa1−xP region the intensity of TO phonon decreases and appearance of considerable TO1 phonon shift up to 350 cm−1 for In content xIn=0.16 was observed. For upper graded layers with xIn from 0.16 to 0.24 the position of GaP-like TO1 was constant and can be ascribed to relaxation of lattice mismatched thin InxGa1−xP graded upper layers in the structure.

[1]  David S. McPhail,et al.  Determination of doping profiles on bevelled GaAs structures by Raman spectroscopy , 2001 .

[2]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[3]  I. Vávra,et al.  Material properties of graded composition InxGa1−xP buffer layers grown on GaP by organometallic vapor phase epitaxy , 2004 .

[4]  L. Peternai,et al.  Advanced light emitting diodes structures for optoelectronic applications , 2003 .

[5]  C. P. Kuo,et al.  Very high‐efficiency semiconductor wafer‐bonded transparent‐substrate (AlxGa1−x)0.5In0.5P/GaP light‐emitting diodes , 1994 .

[6]  H. Casey,et al.  Heterostructure lasers. Part A. Fundamental principles , 1978 .

[7]  J. Nishizawa,et al.  Observation of the characteristic surface morphology of In1-xGaxP epitaxial layers with large lattice mismatch to the GaP substrate , 1986 .

[8]  M. Giehler,et al.  Non-isodisplacement of P atoms in long-wavelength optical phonons in In1–xGaxP , 1979 .

[9]  M. Craford,et al.  Photoluminescence of quasi-direct transitions in disordered In/sub 1-x/Ga/sub x/P/graded GaP alloys , 1997 .

[10]  Martin Zachau,et al.  Luminescence and Raman measurements of InyGa1−yP (0.3 , 1992 .

[11]  C. O. Griffiths,et al.  Study of strain and disorder of InxGa1−xP/(GaAs, graded GaP) (0.25≤x≤0.8) using spectroscopic ellipsometry and Raman spectroscopy , 1994 .

[12]  John B. Shoven,et al.  I , Edinburgh Medical and Surgical Journal.

[13]  K. Benz,et al.  Low temperature growth, and thermodynamic and photoluminescence properties of LPE In1−xGaxP layers , 1985 .

[14]  D. V. Vinokurov,et al.  Observation of a martensitic transition in the Raman spectra of spontaneously ordered GaInP alloys , 1998 .

[15]  R. Kúdela,et al.  Growth and characterisation of InxGa1-xP layers with composition close to crossover from direct to indirect band gap , 2005 .

[16]  E. Bedel,et al.  Comportement à deux modes de Ga(x)In(1 - x)P ? Diffusion Raman résonnante par les modes rendus actifs par le désordre , 1984 .