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Broken gap core-shell nanowires for TFETs

Core-shell nanowires composed of InAs and GaSb are regarded as suitable candidates for future low energy devices such as TFETs. InAs and GaSb form a type III band alignment, also named broken gap, enabling an efficient band-to-band tunneling. Researchers from the PGI9 have now demonstrated the growth by MBE and investigated the morphological and structural characteristics of such nanowires.

It was found that conformal as well as tapered GaSb shells can be grown, solely depending on the growth temperature. TEM investigations showed that the low lattice mismatch between InAs and GaSb of 0.6% results in misfit dislocation free nanowires for shell thicknesses above the critical thickness in planar systems. This demonstrates an efficient strain accommodation in low dimensional systems. HRTEM micrographs indicate smooth surfaces and abrupt interfaces.
The presented nanowires represent the first investigation of conformal III-V core-shell nanowires grown by MBE exhibiting a change of both anions and cations when switching from the core to the shell. (Publication)



Torsten Rieger,