Field effect

About: Field effect is a research topic. Over the lifetime, 4018 publications have been published within this topic receiving 92613 citations.

Correlation between Surface Structure and Surface States at the Clean Germanium (111) Surface

Abstract: A transition from a 2×1 to an 8 structure on the ultrahigh‐vacuum‐cleaved germanium {111} face during heat treatment below 350°C makes germanium particularly well suited as a material for investigating a possible correlation between surface states and surface structure. Individual studies of either the electrical or structural properties of this surface have been made over a number of years, but the present experiment was designed to make both the structural and electrical measurements ``simultaneously'' on the same surface. In the present experiment both surface state density as calculated from surface conductivity and dc‐field effect, and surface structure as characterized by symmetry and spot intensities of the LEED pattern were determined at 30°C as a function of heat treatment over the temperature range 30° to 300°C. The structural changes are accompanied by parallel changes in surface conductivity and field effect mobility. It is concluded that at cleaved germanium surfaces the surface states are es...

Magnetotransport Experiments on Fully Metallic Superconducting Dayem-Bridge Field-Effect Transistors

Abstract: The field effect, as in a field-effect transistor (FET), allows control of the switching current in a metallic superconductor, without affecting the critical temperature or normal-state resistance. Here magnetotransport experiments on Ti-based superconducting FETs reveal several physical insights: The phenomenon occurs at the sample surface, the field effect causes a transition from ballistic to tunnel-like behavior, and a mixed superconducting--normal-metal state is possible at high gate voltages. Such a device could be the cornerstone of easily fabricated monolithic architectures for classical or quantum computing, and a host of other applications in (opto)electronics.

Field-effect-induced gas sensitivity changes in metal oxides

Abstract: The sensitivity of micromachined gas sensor elements with respect to CO, NO, NO2, CH4, H2O and oxygen partial pressure changes was investigated. The microsensors consisted of thin films of RGTO-SnO2 deposited on top of resistively heated Si3N4 membranes. The electrical insulation between the Pt heater and SnO2 sensing layer circuits was provided by a thin dielectric layer. Applying a bias voltage across this layer, field-effect-induced changes in the gas sensing properties could be studied. We find that bias voltage changes can be used to systematically modify the cross-sensitivity of identically prepared sensor elements. These results are relevant for the realisation of monolithically integrated gas sensor arrays.

Oxide-mediated self-limiting recovery of field effect mobility in plasma-treated MoS2

Abstract: Precise tunability of electronic properties of 2D nanomaterials is a key goal of current research in this field of materials science. Chemical modification of layered transition metal dichalcogenides leads to the creation of heterostructures of low-dimensional variants of these materials. In particular, the effect of oxygen-containing plasma treatment on molybdenum disulfide (MoS$_2$) has long been thought to be detrimental to the electrical performance of the material. Here we show that the mobility and conductivity of MoS$_2$ can be precisely controlled and improved by systematic exposure to oxygen:argon plasma, and characterise the material utilising advanced spectroscopy and microscopy. Through complementary theoretical modelling which confirms conductivity enhancement, we uncover the role of a two-dimensional phase of molybdenum trioxide (2D-MoO$_3$) in improving the electronic behaviour of the material. Deduction of the beneficial role of MoO$_3$ will serve to open the field to new approaches with regard to the tunability of 2D semiconductors by their low-dimensional oxides in nano-modified heterostructures.