Hole mobility enhancement in GaAs/p-Al
Ga
As QW-HEMT structures with (4 1 1)A super-flat interfaces grown by MBE |
| |
Authors: | Satoshi Hiyamizu Keisuke Shinohara Kenji Kasahara Yasuyuki Shimizu Satoshi Shimomura Richard A Kiehl |
| |
Abstract: | Be-doped GaAs/p-Al
Ga
As QW-HEMT structures with well width of
and 50 nm were simultaneously grown on (4 1 1)A and (1 0 0) GaAs substrates by MBE. Be-doping concentration in the p-Al
Ga
As layer was
, and the undoped Al
Ga
As spacer layer was 6 nm thick. Hole concentration was about
for
nm. Hole mobility at 10 K in the conventional (1 0 0) samples remained almost constant (about 20 000 cm
(V s) for the current in the
direction) with decreasing
down to 7 nm and it rapidly decreased to 2760 cm
(V s) at
nm. On the other hand, in the (4 1 1)A samples, hole mobility (10 K) increased from 17 500 cm
(V s)
nm) to 33 900 cm
(V s)
nm) and dropped rapidly down to 4090 cm
(V s)
nm) for a current direction of
. This significant enhancement of hole mobility in the (4 1 1)A samples is mainly due to (1) the significantly reduced interface roughness scattering of 2DHG when using the (4 1 1)A super-flat interfaces and (2) the reduced effective mass of holes in the narrow (4 1 1)A QWs (
–20 nm). Shubnikov–de Haas (SdH) measurements on the (4 1 1)A QW sample
nm) confirmed the reduced effective mass (0.30
) of holes. |
| |
Keywords: | (4 1 1)A GaAs/AlGaAs HEMT 2DHG Hall mobility |
本文献已被 ScienceDirect 等数据库收录! |