Ivan Shorubalko

Nonlinear operation of GaInAs/InP-based three-terminal ballistic junctions

We report on nonlinear electrical properties of three-terminal ballistic junctions (TBJs) based on high-electron-mobility GaInAs/InP quantum-well structures. Nonlinear electrical transport behavior of the TBJs is found, and we show a correlation between this behavior and the linear regime of electron transmission in the devices. We also study device geometry effects on these electrical properties of the TBJs. Finally, we demonstrate room-temperature operation of the devices. The results obtained are compared with recent predictions by Xu [H. Q. Xu, Appl. Phys. Lett. 78, 2064 (2001)] and good agreement is found.

Room-temperature and 50 GHz operation of a functional nanomaterial

We demonstrate an artificial electronic nanomaterial, constructed by arrangement of nanometer-sized symmetry-breaking elements into a two-dimensional lattice. The material exhibits intrinsic nonlinear electronic functionality, and therefore functions also as a two-dimensional ratchet. We show that individual devices can be made by simply cutting pieces from the material. We also demonstrate that these devices operate at temperatures up to room temperature and at frequencies at least up to 50 GHz.

Operation of InGaAs/InP-Based Ballistic Rectifiers at Room Temperature and Frequencies up to 50 GHz

Novel semiconductor rectifiers based on ballistic electron transport are fabricated from a high electron-mobility InGaAs/InP wafer. Because the device sizes are sufficiently small, operations at room temperature are achieved. Furthermore, the devices are shown to work not only at least up to 50 GHz but also with a sensitivity roughly the same as commercial microwave diodes, despite the fact that the devices have not yet been optimized. Aspects of using the devices in microwave applications are discussed in terms of the physical mechanism of the novel rectifying effect.

A novel frequency-multiplication device based on three-terminal ballistic junction

In this letter, a novel frequency-multiplication device based on a three-terminal ballistic junction is proposed and demonstrated. A 100 nm-size, three-terminal ballistic junction and a one-dimensional (1D), lateral-field-effect transistor with trench gate-channel insulation are fabricated from high-electron-mobility GaInAs/InP quantum-well material as a single device. The devices show frequency doubling and gain at room temperature. The performance of these devices up to room temperature originates from the nature of the device functionality and the fact that the three-terminal device extensions are maintained below the carrier mean-free path. Furthermore, it is expected that the device performance can be extended up to THz-range.

Nonlinear electrical properties of three-terminal junctions

The authors report on room-temperature electrical measurements of three-terminal junctions made from a semiconductor heterostructure. The correlation between the junction size of the devices and the voltages needed to be applied in order to observe the electrical characteristics of three-terminal ballistic junctions is studied. The authors show that the ballistic behavior of electron transport can be observed in a three-terminal junction with a junction size of a few micrometers, much larger than the mean free path of electrons in the material. The results are explained in terms of a bias-induced enhancement of the electron mean free path in the system.

Novel nanoelectronic triodes and logic devices with TBJs

In this letter, we demonstrate the realization of novel diodes, triodes, and logic gates with three-terminal ballistic junctions (TBJs) made from a semiconductor heterostructure. The approach exploits the ballistic nature of electron transport, which has emerged in the nanostructures. Importantly, we show that TBJs function as logic AND gates and can be used to construct other compound logic gates, such as NAND gates with voltage gain, when combined with a point contact (an inverter). The demonstrated devices show favorable characteristics such as low turn-on voltage in rectification and room-temperature operation.

Tunable nonlinear current–voltage characteristics of three-terminal ballistic nanojunctions

The current–voltage (I–V) characteristics of three-terminal ballistic junctions (TBJs) fabricated from high-electron-mobility GaInAs/InP quantum-well structures are measured in the six-terminal configuration. These characteristics show strong nonlinear, diode-like behavior, in agreement with recent theoretical calculations. Furthermore, the I–V characteristics are tunable by the voltage applied directly to one branch of the TBJs acting as a gate. An additional tuning of the characteristics of the TBJ devices can be performed using an in-plane side gate. All the presented characteristics are measured at room temperature, which makes TBJ devices promising for future nanoelectronic applications.

High frequency characterization of a GaInAs/InP electronic waveguide T-branch switch

We report comprehensive microwave measurements on a T-branch switch; a GaInAs/InP electron waveguide based structure. The study includes a small signal model of the device where limitations of high frequency operation are discussed. An example of large signal operation where the nonlinearity of the device is exploited by operating the T-branch switch as a frequency multiplier is demonstrated.

Symmetry of Two-Terminal Nonlinear Electric Conduction

The well-established symmetry relations for linear transport phenomena cannot, in general, be applied in the nonlinear regime. Here we propose a set of symmetry relations with respect to bias voltage and magnetic field for the nonlinear conductance of two-terminal electric conductors. We experimentally confirm these relations using phase-coherent, semiconductor quantum dots.

Quantum behavior in nanoscale ballistic rectifiers and artificial materials

Low-temperature experiments are performed on nanoscale nonlinear devices (ballistic rectifiers) as well as nanostructured artificial materials, fabricated from an InP/InGaAs quantum well wafer. A dc output is generated between the lower and upper contacts of these devices, when an ac voltage is applied between the left and right contacts. As the temperature is lowered from room temperature, the dc output voltage of the ballistic rectifiers gradually changes from negative to positive. Since the negative output at high temperatures has been well understood in the framework of the classical ballistic electron transport, our results indicate that the electron transport comes into a different physical regime at low temperatures. Furthermore, we find that at even lower temperatures, the devices generate a pronounced oscillatory output as a function of the applied bias. Very similar phenomena are observed in the artificial nanomaterials, suggesting the existence of a common mechanism. We present a simple model based on quantum transport, which explains the key phenomena that we have observed at low temperatures. (Less)