Composition tuning of room-temperature nanolasers

We show that careful preparation conditions enable the preparation of high quality nanoribbons capable of room-temperature lasing covering the complete spectral range from near infrared (NIR) to ultraviolet (UV). Two ternary compound II-VI semiconductors, CdS1−XSeX and ZnYCd1−YS, can be grown on single c-Si substrates to achieve this task. High-resolution transmission electron microscopy and x-ray diffraction showed that the ternary nanoribbons were single phase and single crystal. Room-temperature optical measurements showed that band-gap engineering could be realized via composition modulation in X and Y, with fine tuning of the lasing wavelength via composition changes (ΔX and ΔY) capable of overlapping thermally induced tuning, demonstrating the possibility of continuous tuning in the lasing wavelength throughout the complete 340–710 nm spectral range. We further demonstrate that it is possible to control the spatial composition gradient with sub-mm resolution thus opening the possibility for the fabrication of devices with full spectral optimization.