Optical properties of multi-layer type II InP/GaAs quantum dots studied by surface photovoltage spectroscopy

Ivanov, Ts.; Germanova, K.; Gomes, Paulo F.; Iikawa, F.; Brasil, M. J. S. P.; Cotta, M. A.

doi:10.1063/1.3638705

Cited by 9 publications

(1 citation statement)

References 26 publications

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“…SPV spectroscopy has been widely used in the characterization of bulk materials and various nanostructures. − However, there are relatively few reports in the literature on SPV investigation of SiNWs. SPV spectroscopy was used to study the bandgap of vapor–liquid–solid (VLS)-grown undoped SiNWs and SiNWs doped with P and B, and to conclude on the NW crystal structurewurtzite or diamond .…”

Section: Introductionmentioning

confidence: 99%

Effective Removal of Surface Recombination Centers in Silicon Nanowires Fabricated by Metal-Assisted Chemical Etching

Georgiev

Leontis

Nassiopoulou

2018

ACS Appl. Energy Mater.

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High-density silicon nanowires (SiNWs) were fabricated on p-Si substrates by metal-assisted chemical etching (MACE). A chemical cleaning with HF/piranha/HF was used to remove structural defects from the nanowire surface which are at the origin of surface recombination states. Surface photovoltage (SPV) spectroscopy, capacitance− voltage (C−V), and conductance measurements were used to study the SiNW properties and assess the effectiveness of the cleaning process. For the as-grown samples, the analysis of the SPV amplitude and phase spectra demonstrated high density of positively charged surface recombination centers. These centers increase the surface band bending and decrease the minority carrier lifetime and diffusion length. Si nanostructures at the SiNW surface introduce slow traps, as evidenced by the frequency dispersion at accumulation of the C−V curves and the increase of the diffusion length with frequency. All these features are effectively reduced when the SiNWs are subjected to HF/piranha/HF chemical cleaning. Thus, a cheap and effective way is demonstrated to reduce the surface state density and improve the electronic quality of the surface of SiNWs.

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