Pure Ge quantum well with high hole mobility

We present magneto-transport properties of the two dimensional hole gas (2DHG) in fully strained Ge quantum wells grown on S
i0.2
Ge
0.8
/Si (100) substrates. Comparison is made between heterostructures that are modulation doped in both normal and inverted configurations. Using Shubnikov de Haas oscillations at temperatures down to 90 mK (inverted structure) and to 1.5K (normal structure), an extremely high hole mobility (0.51–1.34) × 10
⁶
cm
²
/Vs has been observed, along with the lowest value of effective mass (0.063–0.070) m
0
to date. The 2DHG is confirmed to be in a pure Ge channel, with low background impurity scattering that improves the 2DHG transport.