Electrical properties of metamorphic In0.52Al0.48As/In0.65Ga0.35As HEMT's on GaAs substrate

Variable magnetic field Hall measurements were performed to investigate the electrical properties in In
_0.52
Al
_0.48
As/In
_0.65
Ga
_0.35
As metamorphic high electron mobility transistors (MMHEMTs) on GaAs substrate at the temperature range from 4 to 100 K. The Shubnikov-de Hass (SdH) measurement shows the two-dimensional electronic behavior and two-subband electron occupation in MMHEMTs. The electron densities and mobilities of the two subbands are obtained by fast Fourier transform analysis. Both the SdH oscillations and conventional Hall analysis are in good agreement in the determination of total electron density, which is about 2.1 times 10
¹²
cm
^-2
due to incomplete transfer of the electrons. The temperature dependence of the electron mobility indicates that at low temperature alloy scattering dominates, whereas at high temperature, the mobility is mainly limited by optical phonon scattering.