Lithographically defined p-channel Si single hole transistors (SHTs) and double quantum dot (DQD) devices are fabricated and characterized. Coulomb oscillations are clearly evident at a temperature of 4.2 K. The charging energy and the diameter of the SHT are estimated from the Coulomb diamonds. Honeycomb-like charge stability diagrams are observed from measurements of the DQD devices. Single hole transitions through the DQD are detected using an integrated SHT as a charge sensor, and a few-hole regime of the DQD is observed. V C 2014 AIP Publishing LLC.[http://dx.doi.org/10.1063/1.4896142] Quantum computers that utilize quantum superposition states have been attracting attention for ultra-fast and parallel calculation applications. The quantum bit (qubit) is the smallest unit of the quantum computer. Various systems of states, such as the position of a charge 1 or polarization direction of light, 2 have been studied for application as qubits. Electron spins in double quantum dots (DQDs) have been proposed with an aim to achieve solid-state spin qubits, 3,4 which have advantages of feasible large-scale integration. The manipulation of electron spins in GaAs DQDs has already been reported; 5-7 however, their coherence time may not be sufficient for the multi-qubits to achieve quantum information processing because of a stronger hyperfine interaction. [8][9][10][11] The electron spins in Si are expected to have small sources of decoherence because there is almost no nuclear spins; 12,13 therefore, Si DQD devices can form large-scale spin qubits with a long coherence time.Si quantum dots (QDs) for electron spin qubits have been formed using various methods; 14-28 however, there are no reports on qubits that employ hole spins in Si, and few reports even on the formation of a single hole transistor (SHT). [29][30][31][32] There are three advantages of holes rather than electrons for spin qubit applications. First, larger p-like symmetry of hole wave functions in the valence band of Si leads to a weaker hyperfine interaction. Second, a moderate spin-orbit interaction 31,32 in the valence band can be used for controlling hole spins as reported in InAs QDs, 33 which can lead to avoid complicated systems such as micro magnets for electron spin resonance using a slanting magnetic field. 34 Third, there are no valley states, which are the cause of the decoherence and difficulties of manipulating the electron spin states. Therefore, hole spins in Si may have more potential as high-performance spin qubits than electron spins.In this paper, we fabricate lithographically-defined ptype Si DQDs and study hole transport properties. A charge sensor (CS) close to the DQD is also fabricated to read out the states of the DQD. 27 Our lithographically-defined QD systems are realized using similar fabrication process to a conventional metal-oxide-semiconductor field-effect transistor (MOSFET). 26,27 Simple integration of the DQD and CS at high density can be possible because of their small size. We demonstrate the detection of charge tra...

Neoglycoconjugates mimicking natural compounds and possessing a variety of biological functions are very successful tools for researchers to understand the general mechanisms of many biological processes in living organisms. These substances are characterized by high biotolerance and specificity, with low toxicity. Due to the difficult isolation of individual glycoclusters from biological objects, special interest has been directed toward synthetic analogs. This review is mainly focused on the one-pot, double-click methodology (containing alkyne–azide click cycloaddition with the following 6π-azaelectrocyclization reactions) used in the synthesis of N-glycoconjugates. Homogeneous (including one type of biantennary N-glycan fragments) and heterogeneous (containing two to four types of biantennary N-glycan fragments) glycoclusters on albumin were synthesized via this strategy. A series of cell-, tissue- and animal-based experiments proved glycoclusters to be a very promising class of targeted delivery systems. Depending on the oligosaccharide units combined in the cluster, their amount, and arrangement relative to one another, conjugates can recognize various cells, including cancer cells, with high selectivity. These results open new perspectives for affected tissue visualization and treatment.

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