Spatial Bandgap Engineering along Single Alloy Nanowires

Abstract

Bandgap engineering of semiconductor nanowires is important in designing nanoscale multifunctional optoelectronic devices. Here, we report a facile thermal evaporation method, and realize the spatial bandgap engineering in single CdS(1-x)Se(x) alloy nanowires. Along the length of these achieved nanowires, the composition can be continuously tuned from x = 0 (CdS) at one end to x = 1 (CdSe) at the other end, resulting in the corresponding bandgap (light emission wavelength) being modulated gradually from 2.44 eV (507 nm, green light) to 1.74 eV (710 nm, red light). In spite of the existing composition (crystal lattice) transition along the length, these multicolor nanowires still possess high-quality crystallization. These bandgap engineered nanowires will have promising applications in such as multicolor display and lighting, high-efficiency solar cells, ultrabroadly spectral detectors, and biotechnology.

Simultaneous two-color lasing in a single CdSSe heterostructure nanosheet

“…The side-by-side arrangement is an important geometry for reaching the respective lasing thresholds of both colors. This is in contrast to structures where bandgap changes along the length of a nanowire [29], where short-wavelength emission from the wide bandgap region (CdS-rich) can be significantly absorbed by the narrow bandgap region (CdSe-rich). Such absorption will increase the threshold for the short wavelength lasing, very often to a degree that is too high to achieve lasing.…”

Vapor-phase preparation of gold nanocrystals by chloroauric acid pyrolysis

“…The average diameter of the nanocrystals decreased from $67 nm to $10 nm when the substrate-to-source distance increased from 3 cm to 6 cm, as indicated by the statistical diagrams. The observed result can be attributed to the different precursor concentration at the different substrate positions [27,28]. It should be noted that though the obtained nanocrystals were highly monodispersed with a uniform size distribution for each substrate, we did not observe clear trend of the particle density when varying the substrate-tosource distance, which might be caused by the instability of the gas flow in the tube furnace during the deposition process.…”

Metal Chalcogenide Hierarchical Nanostructures for Energy Conversion Devices

“…Gu and co-workers used thermal evaporation method to grow CdSSe nanowires. They used CdS and CdSe powders as starting materials separately in a tube furnace (figure 9.9) [33]. They could obtain ultra-long CdSSe nanowires.…”