Related papers: Nondestructive KPFM-assisted Quality Control in Fa…
The study of electron transport in low-dimensional systems is of importance, not only from a fundamental point of view, but also for future electronic and spintronic devices. In this context heterostructures containing a two-dimensional…
We report a non-contact method for conductivity and sheet resistance measurements of graphene samples using a high Q microwave dielectric resonator perturbation technique, with the aim of fast and accurate measurement of microwave…
Wafer-level testing is an important step for process and quality control of electronic chips in integrated circuit (IC) manufacturing which occurs before packaging. The process of wafer probing in its conventional contacting schemes,…
We present a contactless method that is capable of characterizing a high electron mobility transistor heterostructure at the wafer stage, right after its growth, before any production process has been attempted, to provide the equilibrium…
Quality of the electrical contacts and interfaces in various metal/semiconductor/insulator heterostructures is one of the pivotal aspects in both applied and fundamental research areas. For instance, non-optimal contact resistance can limit…
Full size single-sided GaAs microstrip detectors with integrated coupling capacitors and bias resistors have been fabricated on 3'' substrate wafers. PECVD deposited SiO_2 and SiO_2/Si_3N_4 layers were used to provide coupling capacitaces…
We demonstrate a method of making a very shallow, gateable, undoped 2-dimensional electron gas. We have developed a method of making very low resistivity contacts to these structures and systematically studied the evolution of the mobility…
The electrical characterisation of graphene, either in plane sheets or in properly geometrised form can be approached using non-contact methods already employed for thin film materials. The extraordinary thinness (and, correspondingly, the…
Nanolithography based on local oxidation with a scanning force microscope has been performed on an undoped GaAs wafer and a Ga[Al]As heterostructure with an undoped GaAs cap layer and a shallow two-dimensional electron gas. The oxide growth…
We have studied a near-surface two-dimensional electron gas based on an InAs quantum well on a GaAs substrate. In devices without a dielectric layer we estimated large electron mobilities on the order of $10^5$ cm$^2$/Vs. We have observed…
III-V nanowires are comprehensively studied because of their suitability for optoelectronic quantum technology applications. However, their small dimensions and the spatial separation of carriers from the wire surface render electrical…
Engineering and optimization of wireless propagation channels will be one of the key elements of future communication technologies. Metasurfaces may offer a wide spectrum of functionalities for passive and tunable reflecting devices,…
We present a surface passivation method that reduces surface-related losses by almost two orders of magnitude in a highly miniaturized GaAs open microcavity. The microcavity consists of a curved dielectric distributed Bragg reflector (DBR)…
We report resistivity measurements from 0.03 K to 10 K in a dilute high mobility 2D electron system. Using an undoped GaAs/AlGaAs heterojunction in a gated field-effect transistor geometry, a wide range of densities, $0.16 \times 10^{10}…
A method to fabricate GaAs microcavities using only a soft mask with an electrolithographic pattern in an inductively coupled plasma etching is presented. A careful characterization of the fabrication process pinpointing the main routes for…
Kelvin probe force microscopy (KPFM) is a powerful tool for studying contact electrification, using an tiny tip to image voltages caused by transferred charge. It has been used in stationary studies focused on finding patterns (e.g.…
We demonstrate an efficient core-shell GaAs/AlGaAs nanowire photodetector operating at room temperature. The design of this nanoscale detector is based on a type-I heterostructure combined with a metal-semiconductor-metal (MSM) radial…
Oxidation of two-dimensional (2D) layered materials has proven advantageous in creating oxide/2D material heterostructures, opening the door for a new paradigm of low-power electronic devices. Gallium (II) sulfide ($\beta$-GaS), a hexagonal…
A metallic ring based, diode-integrated, low-profile, power-dependent, reflective metasurface working from 3 GHz to 3.6 GHz is proposed in this letter. Unlike the previous study which shifts a band up and down to change the impedance of the…
High performance InGaAs gate-all-around (GAA) nanowire MOSFETs with channel length (Lch) down to 20nm have been fabricated by integrating a higher-k LaAlO3-based gate stack with an equivalent oxide thickness of 1.2nm. It is found that…