Maximum drift velocity of electrons in selectively doped InAlAs/InGaAs/InAlAs heterostructures with InAs inserts

The dependence of the electron mobility and drift velocity on the growth conditions, thickness, and doping of an InAs insert placed at the center of the quantum well in a selectively doped InAlAs/InGaAs/InAlAs heterostructure has been investigated. Record enhancement of the maximum drift velocity to (2–4) $\times$ 10$^7$ cm/s in an electric field of 5 $\times$ 10$^3$ V/cm has been obtained in a 17-nm-wide quantum well with an undoped 4-nm-thick InAs insert. In the structures with additional doping of the InAs insert, which facilitates an increase in the density of electrons in the quantum well to 4.0 $\times$ 10$^{12}$ cm$^{-2}$, the maximum drift velocity is as high as 2 $\times$ 10$^7$ cm/s in an electric field of 7 $\times$ 10$^3$ V/cm.