Radiation effects on GaAs/AlGaAs core/shell ensemble nanowires and nanowire infrared photodetectors

Abstract

With the recent advances in nanowire (NW) growth and fabrication, there has been rapid development and application of GaAs NWs in optoelectronics. It is also of importance to study the radiation tolerance of optoelectronic nano-devices for atomic energy and space-based applications. Here, photoluminescence (PL) and time-resolved photoluminescence measurements were carried out on GaAs/AlGaAs core/shell NWs at room temperature before and after 1 MeV proton irradiation with fluences ranging from 1.0 × 10-3.0 × 10 cm. It is found that the GaAs/AlGaAs core/shell NWs with smaller diameter show much less PL degradation compared with the ones with larger diameters. The increased radiation hardness is mainly attributed to the improvement of a room temperature dynamic-annealing mechanism near the surface of the NWs. We also found that the minority carrier lifetime is closely related to both the PL intensity and defect density induced by irradiation. Finally, GaAs/AlGaAs ensemble NW photodetectors operating in the near-infrared spectral regime have been demonstrated. The influence of proton irradiation on light and dark current characteristics also indicates that NW structures are a good potential candidate for radiation harsh-environment applications.

Corner and side localization of electrons in irregular hexagonal semiconductor shells

“…Due to the crystallographic structure the cross section of such wires is usually hexagonal [1][2][3][4][5][6][7], but other shapes like triangles [8][9][10][11][12][13][14] or dodecagons [15] have already been obtained. These radial heterojunctions have been in the focus of extensive experimental [4][5][6][7][16][17][18][19][20][21] and theoretical [22][23][24] studies in the recent years. This is mostly due to the possibility of controlling some of their physical properties, e.g., the band alignment.…”

Simulation Study on the Defect Generation, Accumulation Mechanism and Mechanical Response of GaAs Nanowires under Heavy-Ion Irradiation

“…Afterward, Li et al carried out 1 MeV proton and H + irradiation experiments on GaAs/AlGaAs core-shell NWs at room temperature and found that the minority carrier lifetime is closely related to the irradiation-induced defect density by photoluminescence (PL) method. In addition, the size dependence of the carrier lifetime damage factor of GaAs NWs is mainly attributed to a special dynamic mechanism of defect annihilation, as summarized by them [14,15]. These results generally indicate that NW is a better candidate structure for radiation resistance.…”

Optical Modelling of GaAs/GaSb Core-Shell Cone Topped Octagonal Faced Nanopillar Array with Periodic Trapezoidal Textured Cut for High Photon Trapping Efficiency

“…This constraint is overcome by the core-shell nanopillar structure. Core-shell p-n junction embedded within the nanopillar structure allows orthogonalization of the photon absorption and carrier collection direction [12,13]. Owing to this the minority carriers travel a shorter path length as compared to the minority diffusion length.…”