A gate-defined silicon quantum dot molecule

We report electron transport measurements of a silicon double dot formed in multi-gated metal-oxide-semiconductor structures with a 15-nm-thick silicon-on-insulator layer. Tunable tunnel coupling enables us to observe an excitation spectrum in weakly coupled dots and an energy level anticrossing in strongly coupled ones. Such a quantum dot molecule with both charge and energy quantization provides the essential prerequisite for future implementation of silicon-based quantum computations.Comment: 11pages,3figure

Pauli-Spin-Blockade Transport through a Silicon Double Quantum Dot

We present measurements of resonant tunneling through discrete energy levels of a silicon double quantum dot formed in a thin silicon-on-insulator layer. In the absence of piezoelectric phonon coupling, spontaneous phonon emission with deformation-potential coupling accounts for inelastic tunneling through the ground states of the two dots. Such transport measurements enable us to observe a Pauli spin blockade due to effective two-electron spin-triplet correlations, evident in a distinct bias-polarity dependence of resonant tunneling through the ground states. The blockade is lifted by the excited-state resonance by virtue of efficient phonon emission between the ground states. Our experiment demonstrates considerable potential for investigating silicon-based spin dynamics and spin-based quantum information processing.Comment: 10 pages,3 figure

Analysis of Hole Lifetime in SOI MOSFET Single-Photon Detector

Hole lifetime in the silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor (MOSFET) singlephoton detector was evaluated by the analysis of drain current histograms for different light intensities and substrate voltages. It was found that the peaks in the histogram corresponding to the larger number of stored holes grew as the gate bias decreased. This was attributed not to the increased light absorption efficiency or collection efficiency of the photo-generated holes, but to the prolonged hole lifetime presumably caused by the higher transverse electric field inside the body of SOI MOSFET

Analysis of current noise in MOSFET-based charge-transfer device

Low-frequency current noise in the MOSFET-based charge-transfer devices was evaluated at room and cryogenic temperatures. Excessive noise, whose power was 25-50 times larger than that of room temperature, was observed at 20 K, and this hindered the accurate transfer of charge. Interestingly, the noise power was proportional to the square of the pulse frequency that drove the gates in these devices, and an expression for the noise was proposed to correlate it with the frequency, gate capacitance and fluctuation of the threshold voltage at the gate