Some material parameters, such as lattice constant, crystal density, thermal expansion coefficient, dielectric constant, and elastic constant, obey Vegard’s rule well. Of particular interest is the deviation of material parameters from linearity with respect to the AlAs mole fraction x. The material parameters and properties considered in the present review can be classified into sixteen groups: (1) lattice constant and crystal density, (2) melting point, (3) thermal expansion coefficient, (4) lattice dynamic properties, (5) lattice thermal properties, (6) electronic‐band structure, (7) external perturbation effects on the band‐gap energy, (8) effective mass, (9) deformation potential, (10) static and high‐frequency dielectric constants, (11) magnetic susceptibility, (12) piezoelectric constant, (13) Fröhlich coupling parameter, (14) electron transport properties, (15) optical properties, and (16) photoelastic properties. The model used is based on an interpolation scheme and, therefore, necessitates known values of the parameters for the related binaries (GaAs and AlAs). A complete set of material parameters are considered in this review for GaAs, AlAs, and Al xGa 1− xAs alloys. The purpose of this review is (i) to obtain and clarify all the various material parameters of Al xGa 1− xAs alloy from a systematic point of view, and (ii) to present key properties of the material parameters for a variety of research works and device applications. Recently, Blakemore has presented numerical and graphical information about many of the physical and electronic properties of GaAs. Even though the basic Al xGa 1− xAs/GaAs heterostructure concepts are understood at this time, some practical device parameters in this system have been hampered by a lack of definite knowledge of many material parameters. The Al xGa 1− xAs/GaAs heterostructure system is potentially useful material for high‐speed digital, high‐frequency microwave, and electro‐optic device applications.
0 kommentar(er)
