Group IV alloys have attracted interest in the drive to create Si compatible, direct band gap materials for implementation in complementary metal oxide semiconductor (CMOS) and beyond CMOS devices. The lack of a direct band gap in Si and Ge hinders their incorporation into optoelectronic and photonic devices, without the induction of undesirable strain. Alloying of Ge with Sn represents a novel solution to the lack of light emission in group IV compounds, with an indirect-to-direct band gap transition predicted for Ge at a Sn incorporation greater than 6.5 atom %. Recently, the initiatives on the GeSn alloy research have turned its focus to nanoforms to keep on track with the miniaturization of Si-related platforms for application in nano/ optoelectronics, photonics, and energy devices. Here, we review recent advances in the growth and application of Ge 1−x Sn x nanomaterials. An overview of the theoretical band structure calculations for Ge 1−x Sn x and the effect of band mixing is briefly explored to highlight the significance of Sn inclusion in Ge for band gap engineering. Different fabrication methods for growing Ge 1−x Sn x alloy nanostructures are delineated and correlated with thin film growth. This highlights the requirement of low-temperature and kinetically driven nonequilibrium processes for growing these metastable nanoscale alloys. The optical and electrical properties for both Ge 1−x Sn x strain-relaxed one-dimensional (1D) nanostructures and nanoparticles are reported as well as recent key research findings on Ge 1−x Sn x thin films, highlighting the potential application of these materials in photonic, nanoelectronic, and optotelectronic devices.

Background Gold nanorods (AuNRs), due to the optical and electronic properties namely the surface plasma resonance, have been developed to achieve the light-mediated photothermal therapy (PTT) for cancer. However, PTT alone may suffer from inefficient tumor killing. Recently, the combination of PTT and chemotherapy has been utilized to achieve synergistic anticancer effects. Methods In this study, AuNRs capped with hexadecyltrimethylammonium bromide (CTAB), poly(acrylic acid) (PAA), and PEGylated anisamide (a ligand known to target the sigma receptor) have been developed to produce a range of negatively charged anisamide-targeted PEGylated AuNRs (namely Au-CTAB-PAA-PEG-AA) for the combination of PTT and chemotherapy (termed as chemo-photothermal therapy [CPTT]). Epirubicin (EPI, an anthracycline drug) was efficiently loaded onto the surface of Au 800 -CTAB-PAA-PEG-AA via the electrostatic interaction forming Au 800 -CTAB-PAA-PEG-AA.EPI complex. Results The resultant complex demonstrated pH-dependent drug release, facilitated nucleus trafficking of EPI, and induced antiproliferative effects in human prostate cancer PC-3 cells. When Au 800 -CTAB-PAA-PEG-AA.EPI complex was further stimulated with desired laser irradiation, the synergistic outcome was evident in PC-3 xenograft mice. Conclusion These results demonstrate a promising strategy for clinical application of CPTT in cancer.

Ge nanowires are playing a big role in the development of new functional microelectronic modules, such as gate-all-around field-effect transistor devices, on-chip lasers and photodetectors. The widely used three-phase bottom-up growth method utilising a foreign catalyst metal or metalloid is by far the most popular for Ge nanowire growth. However, to fully utilise the potential of Ge nanowires, it is important to explore and understand alternative and functional growth paradigms such as self-seeded nanowire growth, where nanowire growth is usually directed by the in situ-formed catalysts of the growth material, i.e., Ge in this case. Additionally, it is important to understand how the self-seeded nanowires can benefit the device application of nanomaterials as the additional metal seeding can influence electron and phonon transport, and the electronic band structure in the nanomaterials. Here, we review recent advances in the growth and application of self-seeded Ge and Ge-based binary alloy (GeSn) nanowires. Different fabrication methods for growing self-seeded Ge nanowires are delineated and correlated with metal seeded growth. This review also highlights the requirement and advantage of self-seeded growth approach for Ge nanomaterials in the potential applications in energy storage and nanoelectronic devices.