In-plane InGaAs/Ga(As)Sb nanowire based tunnel junctions grown by selective area molecular beam epitaxy

Abstract

In-plane InGaAs/Ga(As)Sb heterojunction tunnel diodes are fabricated by selective area molecular beam epitaxy with two different architectures: either radial InGaAs core / Ga(As)Sb shell nanowires or axial InGaAs/GaSb heterojunctions. In the former case, we unveil the impact of strain relaxation and alloy composition fluctuations at the nanoscale on the tunneling properties of the diodes, whereas in the latter case we demonstrate that template assisted molecular beam epitaxy can be used to achieve a very precise control of tunnel diodes dimensions at the nanoscale with a scalable process. In both cases, negative differential resistances with large peak current densities are achieved.

Improving the intrinsic conductance of selective area grown in-plane InAs nanowires with a GaSb shell

“…After the removal of the InP oxide as described above for sample C, a 100 nm thick GaSb layer is first grown at a temperature of 470 °C, with a growth rate of 0.1 ML.s −1 , a Sb/Ga flux ratio of 2.5 and under atomic hydrogen exposure. These conditions have been demonstrated suitable for selective epitaxy as well as to optimize the GaSb nanostructure morphology on GaAs or InP (001) substrates [21,28]. InAs is then deposited on the GaSb nano-template with a nominal deposited thickness of 10 nm.…”