Influence of nanoscale faceting on the tunneling properties of near broken gap InAs/AlGaSb heterojunctions grown by selective area epitaxy

Abstract

We report on the selective area molecular beam epitaxy of InAs/AlGaSb heterostructures on a GaSb (001) substrate. This method is used to realize Esaki tunnel diodes with a tunneling area down to 50 nm × 50 nm. The impact of the size reduction on the peak current density of the diode is investigated, and we show how the formation of the InAs facets can deeply affect the band-to-band tunneling properties of the heterostructure. This phenomenon is explained by the surface-dependent incorporation of Si dopant during growth.

Phosphorene/rhenium disulfide heterojunction-based negative differential resistance device for multi-valued logic

“…1h). Therefore, a highly doped n + /p + heterojunction can easily be implemented by forming a broken-gap band alignment without using a separate doping process, such as electrostatic doping by gate bias or chemical doping, which is generally required in a type-II heterojunction to realize a NDR device2346733343536.…”

“…Recently, negative differential resistance (NDR) devices have attracted considerable attention owing to their folded current–voltage ( I – V ) characteristic (N-shaped I – V curve), which presents multiple threshold voltage values123456789101112131415161718192021222324252627. Because of this remarkable property, studies associated with the NDR devices have been explored for realizing multi-valued logic (MVL) applications17111326.…”

“…The NDR devices that have been researched for the implementation of this MVL system are Esaki diodes234567, resonant tunnelling diodes891011121314151617181920, Gunn diodes, single electron transistors2122 and molecular devices2324. However, at the current stage of research, because most of the Esaki diodes and resonant tunnelling diodes were fabricated in Si–Ge and III–V semiconductors234891011121314, the formation of various types of heterojunctions (type-I, II and III) is limited by threading dislocations, which are normally caused at the junction interface by lattice mismatch during film growth. Although the threading dislocation that increases the valley current of NDR device can be reduced by applying superlattice and nanowire structures, it is hard to avoid that the fabrication process becomes more complex.…”

“…Because these 2D semiconductor layers are stacked via weak van der Waals interaction, 2D materials-based heterojunctions do not suffer from lattice mismatch and form atomically sharp interfaces, allowing high-quality heterojunction interfaces293031. It is also possible to design various heterojunctions by stacking different 2D materials with different bandgaps and electron affinities, where band structure alignment can be classified into three types: type-I (straddling gap)32, type-II (staggered gap)2346733343536 and type-III (broken gap)532. Recently, Roy et al 6.…”

Staggered band gap n+In0.5Ga0.5As/p+GaAs0.5Sb0.5 Esaki diode investigations for TFET device predictions

“…This allows a higher ratio of on-current to off-current (I on /I off ) at reduced operating voltage V dd (o0.5 V) as compared to the state of the art FinFET devices which are considered nowadays key in power consumption scaling [3]. Major studies are pointing towards III-V hetero configurations as ideal material systems in order for TFET to be competitive with MOSFET [1][2][3][4][5][6][7][8][9][10]. However, III-V TFET still show inconsistency in measured vs. simulated I on /I off and subthreshold characteristics [2].…”