Demonstration of GaAsSb/InAs nanowire backward diodes grown using position-controlled vapor–liquid–solid method

Abstract

p-GaAsSb/n-InAs type-II nanowire (NW) diodes were fabricated using the position-controlled vapor–liquid–solid growth method. InAs and GaAsSb NW segments were grown vertically on GaAs(111)B substrates with the assistance of Au catalysts. Transmission electron microscopy-energy-dispersive X-ray spectroscopy analysis revealed that the GaAsSb segments have an Sb content of 40%, which is sufficient to form a tunnel heterostructure. Scanning capacitance microscope images clearly indicated the formation of a p–n junction in the NWs. Backward diode characteristics, that is, current flow toward negative bias originating from a tunnel current and current suppression toward positive bias by a heterobarrier, were demonstrated.

Selective-Area Growth of Vertical InGaAs/GaSb Core–Shell Nanowires on Silicon and Dual Switching Properties

“…GaSb-related NWs were first synthesized by the vapor–liquid–solid method, which enabled the formation of InAs/GaSb axial and GaSb/InAs core–shell (CS) NWs. These NWs performed as backward diode, n/p-channel vertical FETs, cointegrated vertical FETs, and vertical TFETs. , There was, however, still a challenge in improving the device performance and lowering both the leakage current and the SS in switching devices. One of the main factors is that Sb-related III–V epitaxy makes it difficult to form an atomically smooth layer because of a large surfactant effect and unintentional GaSb shell-layer growth on NWs .…”

“…GaSb-related NWs were first synthesized by the vapor− liquid−solid method, which enabled the formation of InAs/ GaSb axial and GaSb/InAs core−shell (CS) NWs. These NWs performed as backward diode, 4 n/p-channel vertical FETs, 5 cointegrated vertical FETs, 6 and vertical TFETs. 2,7 There was, however, still a challenge in improving the device performance and lowering both the leakage current and the SS in switching devices.…”

Type-II p-GaAsSb/n-InAs multi-nanowire backward diodes for rectification of low-power RF signals under a zero-bias condition

“…Trimethyl-indium (TMIn), AsH 3 , and H 2 S were used to grow the n-InAs NW segments at 430 °C, and then p-GaAs 0.6 Sb 0.4 NW segments were grown using triethylgallium (TEGa), AsH 3 , trimethyl-antimony (TMSb), and diethyl-zinc (DEZn) at 520 °C. 23,24) The doping concentrations in the p-GaAs 0.6 Sb 0.4 and n-InAs were estimated to be 4 × 10 18 and 1 × 10 19 cm -3 , respectively. The p-GaAs 0.6 Sb 0.4 /n-InAs NWs had a core-shell structure as described in a previous study.…”

“…The p-GaAs 0.6 Sb 0.4 /n-InAs NWs had a core-shell structure as described in a previous study. 24) The NW diodes were successfully formed on the substrate, although both the p-GaAs 0.6 Sb 0.4 and n-InAs segments were lattice-mismatched to the GaAs substrate. After p-GaAs 0.6 Sb 0.4 /n-InAs NW growth, the surface was fully passivated with a thin 14 nm AlO x film by atomic layer deposition 25) followed by a thick benzocyclobutene (BCB) interlayer film to enable embedding the NWs and planarizing the interlayer.…”

“…The p-GaAsSb shell around the n-InAs core was clearly separated by a depletion layer against the upper p-GaAsSb segment, which was confirmed by scanning capacitance microscopy. 24) A magnified TEM image at a junction region displayed stacking faults in an InAs segment. However, the crystal structure in the GaAs 0.6 Sb 0.4 segment indicated that a significant dislocation was not observed even though the InAs segments had lattice mismatches to a GaAs substrate.…”