Control of Conductivity of In_xGa_1–xAs Nanowires by Applied Tension and Surface States

Abstract

The electronic properties of semiconductor AIIIBV nanowires (NWs) due to their high surface/volume ratio can be effectively controlled by NW strain and surface electronic states. We study the effect of applied tension on the conductivity of wurtzite In x Ga 1−x As (x ∼ 0.8) NWs. Experimentally, conductive atomic force microscopy is used to measure the I−V curves of vertically standing NWs covered by native oxide. To apply tension, the microscope probe touching the NW side is shifted laterally to produce a tensile strain in the NW. The NW strain significantly increases the forward current in the measured I−V curves. When the strain reaches 4%, the I−V curve becomes almost linear, and the forward current increases by 3 orders of magnitude. In the latter case, the tensile strain is supposed to shift the conduction band minima below the Fermi level, whose position, in turn, is fixed by surface states. Consequently, the surface conductivity channel appears. The observed effects confirm that the excess surface arsenic is responsible for the Fermi level pinning at oxidized surfaces of III-As NWs.

Effect of the Uniaxial Compression on the GaAs Nanowire Solar Cell

“…Recently, it was shown that the Fermi level in III-As semiconductors was pinned due to the formation of excess surface arsenic at the oxidized or metalized surface [45]. The position of pinning (effective work function) was~4.8 eV for n-type and~4.95 eV for p-type semiconductors, implying insensitivity to mechanical deformation [46,47]. During modeling, the work function of the contact was set at Φ eff n = 4.8 and Φ eff p = 4.95 eV for n-type and p-type GaAs, respectively.…”

Schottky‐Contacted High‐Performance GaSb Nanowires Photodetectors Enabled by Lead‐Free All‐Inorganic Perovskites Decoration

“…Furthermore, the Schottky barrier between semiconductor and metal electrode can reduce the dark current of photodetectors. [18,[27][28][29] Beyond surface passivation, the construction of core-shell NWs and the introduction of stress, etc., [30][31][32][33][34] surface decoration is becoming a popular approach to control the surface Fermi level pinning effect of semiconductors' NWs. [35] With decoration, the carriers will transfer at the interfaces between NWs and decorated semiconductors, The surface Fermi level pinning effect promotes the formation of metalindependent Ohmic contacts for the high-speed GaSb nanowires (NWs) electronic devices, however, it limits next-generation optoelectronic devices.…”

Effect of crystal structure on the Young’s modulus of GaP nanowires

“…High deformation stability of NWs allows to control their electronic and optoelectronic properties by elastic strains. Particularly, for III-As (InAs, GaAs, InGaAs) NWs a 2% mechanical deformation was shown to redshift the photoluminescence position by 290 meV [7] or change NW conductivity by four orders of magnitude [8,9]. Non-zero piezoelectric coefficients along the NW growth axis (111) in zinc-blende (ZB) and wurtzite (WZ) NWs allow enhancing characteristics of sensors [10], light-emitting diodes [11], ambient mechanical energy harvesters [5,12], photodetectors [13,14], and solar cells [15].…”