High-Mobility Helical Tellurium Field-Effect Transistors Enabled by Transfer-Free, Low-Temperature Direct Growth.

The transfer-free direct growth of high-performance materials and devices can enable transformative new technologies. Here, room-temperature field-effect hole mobilities as high as 707 cm2 V-1 s-1 are reported, achieved using transfer-free, low-temperature (≤120 °C) direct growth of helical tellurium (Te) nanostructure devices on SiO2 /Si. The Te nanostructures exhibit significantly higher device performance than other low-temperature grown semiconductors, and it is demonstrated that through careful control of the growth process, high-performance Te can be grown on other technologically relevant substrates including flexible plastics like polyethylene terephthalate and graphene in addition to amorphous oxides like SiO2 /Si and HfO2 . The morphology of the Te films can be tailored by the growth temperature, and different carrier scattering mechanisms are identified for films with different morphologies. The transfer-free direct growth of high-mobility Te devices can enable major technological breakthroughs, as the low-temperature growth and fabrication is compatible with the severe thermal budget constraints of emerging applications. For example, vertical integration of novel devices atop a silicon complementary metal oxide semiconductor platform (thermal budget <450 °C) has been theoretically shown to provide a 10× systems level performance improvement, while flexible and wearable electronics (thermal budget <200 °C) can revolutionize defense and medical applications.