Wavelength-tunable lasing in single-crystalCdS1−XSeX nanoribbons

Abstract

Alloyed ternary CdS1−XSeX nanoribbonsof variable composition X were synthesized by the combination of thermal evaporation and laser ablation.High-resolution transmission electron microscopy and x-ray diffraction showed that the ternaryCdS1−XSeX nanoribbons were single phase and highly crystalline. Room-temperatureoptical measurements showed that band-gap engineering could be realized inCdS1−XSeX nanoribbons via modulation in compositionX. Lasingemission between the band-gap energy of CdS (512 nm) and that of CdSe (710 nm) was observed forcomposition 0<X<1 under optical pumping (266 nm) at power densities of35–60 kW cm−2. Cathodoluminescence imaging and spectroscopy of singleCdS1−XSeX nanoribbons reveal the uniform optical properties of the nanoribbons, which supports theabsence of phase segregation within the nanoribbon. Fine tuning of the lasing wavelengthvia composition changes is shown to be smaller than 0.1 nm, and is capable of overlappingthermally induced tuning, demonstrating the possibility of continuous tuning in the lasingwavelength. The broad and fine tunable lasing properties of ternary nanoribbons havepotential applications in color-tuned nanolasers, biological labels, and nano-optoelectronics.