N‐Doped InGaP Nanowire Shells in GaAs/InGaP Core–Shell p–n Junctions

Abstract

Herein, the characterization of n‐doped InGaP:Si shells in coaxial not‐intentionally doped (nid)‐GaAs/n‐InGaP as well as n–p–n core–multishell nanowires grown by metalorganic vapor‐phase epitaxy is reported. The multi‐tip scanning tunneling microscopy technique is used for contact‐independent resistance profiling along the tapered nid‐GaAs/n‐InGaP core–shell nanowires to estimate the established emitter shell doping concentration to ND ≈ 3 · 1018 cm−3. Contacts on these shells are demonstrated and exhibit ohmic current–voltage characteristics after annealing. Application potential is demonstrated by the growth and processing of coaxial p‐GaAs/n‐InGaP junctions in n–p–n core–multishell nanowires, with n‐InGaP being the electron‐supplying emitter material. Current–voltage characteristics and temperature‐dependent electroluminescence measurements substantiate successful doping of the n‐InGaP shell. A tunneling‐assisted contribution to the leakage currents of the investigated p–n junctions is verified by the sub‐bandgap luminescence at low temperatures and is attributed to radiative tunneling processes.