Emission energy, exciton dynamics and lasing properties of buckled CdS nanoribbons

Abstract

We report the modulation of emission energy, exciton dynamics and lasing properties in a single buckled CdS nanoribbon (NR) by strain-engineering. Inspired by ordered structure fabrication on elastomeric polymer, we develop a new method to fabricate uniform buckled NRs supported on polydimethylsiloxane (PDMS). Wavy structure, of which compressive and tensile strain periodically varied along the CdS NR, leads to a position-dependent emission energy shift as large as 14 nm in photoluminescence (PL) mapping. Both micro-PL and micro-reflectance reveal the spectral characteristics of broad emission of buckled NR, which can be understood by the discrepancy of strain-induced energy shift of A- and B-exciton of CdS. Furthermore, the dynamics of excitons under tensile strain are also investigated; we find that the B-exciton have much shorter lifetime than that of redshifted A-exciton. In addition, we also present the lasing of buckled CdS NRs, in which the strain-dominated mode selection in multi-mode laser and negligible mode shifts in single-mode laser are clearly observed. Our results show that the strained NRs may serve as new functional optical elements for flexible light emitter or on-chip all-optical devices.

Dynamical Tuning of Nanowire Lasing Spectra

“…Thus, this model concept is fully suitable for explaining the experimental observations. Furthermore, our nanolaser device concept shows strong benefits in comparison to previously demonstrated (static) strain tuning in buckled CdS microribbon lasers, as it avoids a possible diffusion of the photoexcited carriers out of the cavity and gain medium …”

“…Uniaxial stress is a powerful tool for the dynamical emission control in NW laser devices which might pave the way for novel highly functional nanoscale spectroscopic devices in combination with MEMS architectures. Indeed, for evoking strain values of up to ±(3–4) % in such tunable nanolasers designs, a shift of the gain envelope of over ±10 nm should be achievable . Additionally, beyond the spectral emission control, this concept might enforce research on nanosensing (see concept Figure S7a in the Supporting Information), nanoscale signal tuning devices such as periodic emission modulators (Supporting Information Figure S7b), tunable waveguides, and tunable absorbers.…”

Optical Waveguide of Buckled CdS Nanowires Modulated by Strain-Engineering

“…Strain-engineering has been verified to be an efficient method to tune wavelength, polarization, emitting intensity of light, and also carrier dynamics in nanomaterials. − Benefited from large surface–volume ratio and high crystal quality, semiconductor nanostructures can still retain elasticity even suffering from very large stress. And hence, new opportunities for flexible device applications would be opened when strain-engineering meets semiconductor nanostructures.…”