COMPLEMENTARY ELECTRONIC DEVICES BASED ON TWO-DIMENSIONAL TELLURIUM
The exploration of tellurene as a large-area, stable p-type semiconductor has been a key focus of research for several years. In my work, I have made notable strides by successfully fabricating ambipolar Te-FETs using contact engineering techniques. Notably, we observed that the polarity characteristics of Te flakes depend on their thickness: thinner flakes exhibit p-type behavior, while thicker ones show n-FET characteristics.
To better understand the carrier transport mechanism in 2D Te FETs, we developed a novel "sandwich" model. This model accounts for the differing properties of the surface layer compared to the inner layers, combining insights from both experimental data and advanced simulations. By addressing the variations between the surface and the body layers, we have gained new insights into the thickness-dependent polarity of Te FETs—an area previously explained through band structure alignment theory in other 2D semiconductors.
Surface native oxide's influence on FET transport has often been neglected in similar materials. However, in our research, we specifically focused on charge transfer doping caused by Te's native oxide. By directly reducing the surface oxide layer, we highlighted the importance of environment-induced surface defects, like native oxide, which are almost unavoidable in nanoelectronics based on 2D materials. These defects result in a chemically distinct surface composition, causing band bending in the out-of-plane direction near the surface.
In addition to these fundamental findings, we reached a significant practical milestone by successfully constructing a monolithic CMOS inverter. This was achieved through careful control of Te thickness and contact design, ensuring optimal device performance. We also advanced polarity engineering by demonstrating a homojunction based on Te flakes of different thicknesses, showcasing the versatility and potential of polarity control in 2D materials. This has exciting implications for the development of photodetectors and photovoltaic devices.
Overall, our research provides important insights into the transport mechanisms and polarity engineering of 2D semiconductors, with a particular focus on tellurene. Our findings not only enhance the understanding of Te FETs but also have broader implications for the field of 2D materials and their applications in advanced electronics.
History
Degree Type
- Doctor of Philosophy
Department
- Industrial Engineering
Campus location
- West Lafayette