Epitaxial High-Yield Intrinsic and Te-Doped Dilute Nitride GaAsSbN Nanowire Heterostructure and Ensemble Photodetector Application

Abstract

Band gap engineering of GaAsSbN nanowires (NWs) grown by Ga-assisted molecular beam epitaxy and demonstration of a Te-doped axial GaAsSbN NW-based Schottky barrier photodetector on p-Si (111) in the near-infrared region are reported. Stringent control on NW nucleation conditions, stem growth duration, and NW exposure to the N-plasma were found to be critical for the successful growth of high-quality dilute nitride quaternary GaAsSbN NWs in the axial configuration. Planar defect-free structures were realized with room temperature photoluminescence (PL) characteristics, revealing reduced N-induced point defects and nonradiative recombination centers. N incorporation in the dilute nitride NWs was ascertained from PL and Raman spectral mode shifts and shapes and weak temperature-dependent PL peak energy. The advantage of Te-doping in dilute nitride NWs using a GaTe captive source is the compensation of point defects, as evidenced by a significant improvement in PL characteristics, Raman mode shifts, and spectral shape, with improved photodetector device performance relative to intrinsic dilute nitride NWs. Te-doped GaAsSbN NW Schottky-based photodetectors have been demonstrated on both single and ensemble configurations with a resultant responsivity of 5 A/W at 860 nm and 3800 A/W at 1100, respectively. Detectivity of 3.2 × 10 10 Jones was achieved on the Te-doped ensemble NW device. The findings presented in this work showcase prospects for rich band gap engineering using doped GaAsSbN NWs for near-infrared region device applications.

GaAs/GaAsSb Core–Shell Configured Nanowire-Based Avalanche Photodiodes up to 1.3 μm Light Detection

“…This indicates that the generation of photocarriers is not dominated by impact-ionization, but by photo-absorption up to 8 V reverse bias, beyond which the E -field strength is sufficient to initiate the exponential impact ionization process. A unity-gain responsivity of 0.2–0.25 A/W is achieved at ∼1.8 V, which is higher than reported values for pure GaAs NWs and comparable to the GaAs NW APDs. , The computation of device responsivity in this work is discussed elsewhere . It was noted that the device showed a marginal increase in dark current after shining light, and we attribute this observation to the trap filling on illumination and slow release of carriers by the traps thereafter under dark DC sweep (Supporting S5a).…”

“…1,45 The computation of device responsivity in this work is discussed elsewhere. 46 It was noted that the device showed a marginal increase in dark current after shining light, and we attribute this observation to the trap filling on illumination and slow release of carriers by the traps thereafter under dark DC sweep (Supporting S5a). Figure 3b shows the result of repeated DC voltage sweeps on V BR at 200 K. A considerable fluctuation in the breakdown voltage is observed during the initial sweeps, with the fluctuation range decreasing and a decrease in dark current on repeated DC I−V sweeps (inset as shown in Figure 3b).…”

Ensemble GaAsSb/GaAs axial configured nanowire-based separate absorption, charge, and multiplication avalanche near-infrared photodetectors

“…The computation of device responsivity is discussed elsewhere. 24 The I – V characteristics of the NW APD device were measured by limiting the current compliance of the measurement system to 10 −4 A, as the NW APD devices were found to degrade during the operation at higher current conduction (ESI S5 † ).…”

MBE-Grown Hybrid Axial Core–Shell n-i-p GaAsSb Heterojunction Ensemble Nanowire-Based Near-Infrared Photodetectors up to 1.5 μm

“…A Carl Zeiss Auriga-BU FIB field emission scanning electron microscope (FESEM) was used to determine the morphology of the NWs. The μ-PL measurements were conducted at 4 K and RT to determine the optical characteristics of the NWs; the details of the setup are provided elsewhere. ,, For ensemble PD, NW samples were spin-coated with an insulating and transparent SU-8 photoresist, which served as a protective layer and filler for NWs. The NW core tip from SU-8 was exposed using reactive ion etching (RIE).…”