Spin--Orbit Interaction in an In0.53Ga0.47As/In0.7Ga0.3As Shallow Two-Dimensional Electron Gas Located 5 nm below InP Surface Barrier

A two-dimensional electron gas (2DEG) formed near a semiconductor surface has an advantage for the injection and detection of electron spins to realize a spin field-effect transistor (spin FET). Here, we investigated the strength of spin--orbit interaction (SOI) in 26.5 nm In 0.52 Al 0.48 As and AlAs surface layer/5 nm InP/7.5 nm In 0.53 Ga 0.47 As/10 nm In 0.7 Ga 0.3 As 2DEGs. By the selective wet etching of In 0.52 Al 0.48 As and InP layers, we achieved a 5 nm InP/In 0.53 Ga 0.47 As/In 0.7 Ga 0.3 As 2DEG with a carrier density of $1.06\times 10^{12}$ cm -2 . Magnetoconductance is measured to evaluate the strength of Rashba SOI by the quantum correction of the conductance in the ballistic regime developed by Golub. The Rashba SOI parameter $\alpha$ reaches $3.85\times 10^{-12}$ eV m, which yields a spin rotation angle of $2.34\pi$ within the elastic scattering length indicating a good candidate for the channel of a spin FET.