Biasing

About: Biasing is a research topic. Over the lifetime, 29422 publications have been published within this topic receiving 301035 citations.

First-principles study of structure and quantum transport properties of C20 fullerene.

Abstract: Using first-principles density-functional theory and nonequilibrium Green's function formalism for quantum transport calculation, we study the electronic and transport properties of C(20) fullerene molecule. Our results show that the equilibrium conductance of C(20) molecule is near 1G(0). It is found that the I-V curve displays a linear region centered about V = 0 and nonlinear behavior under higher bias voltages and an obvious negative differential resistance phenomenon in a certain bias voltage range. The mechanism for the negative differential resistance behavior of C(20) is suggested. The present findings could be helpful for the application of the C(20) molecule in the field of single molecular devices or nanometer electronics.

Bias-Voltage Driven Switching of the Charge-Density-Wave and Normal Metallic Phases in 1T-TaS2 Thin-Film Devices.

Abstract: We report on switching among three charge-density-wave phases, commensurate, nearly commensurate, incommensurate, and the high-temperature normal metallic phase in thin-film 1T-TaS2 devices induced...

Non-volatile semi-conductor memory device with double gate structure

Abstract: A memory cell structure for a non-volatile semiconductor memory has a semiconductor substrate and first and second diffusion layers having a conductivity type opposite to that of the substrate, formed on the substrate and serve as a source and a drain. The second diffusion layer is coupled through a contact hole to a conductive layer that serves as a bit line. The functions of the first and second diffusion layers as the source and drain are reversed between data write and read modes. A floating gate and a control gate are insulatively provided on the substrate in parallel to each other. In either the data write mode or data read mode, the first and second diffusion layer are applied with a bias voltage while the control gate is initially applied with a ground voltage. A memory cell is selected by dropping the bias voltage on the second diffusion layer. The potential on the first diffusion layer is kept unchanged to constantly maintain the initially-applied bias voltage even when the memory cell is selected, so that the first diffusion layer is permitted to be coupled to the common wiring line together with the corresponding first diffusion layers of the other memory cells.

Suppression of dark current in germanium-tin on silicon p-i-n photodiode by a silicon surface passivation technique.

Abstract: We demonstrate that a complementary metal-oxide-semiconductor (CMOS) compatible silicon (Si) surface passivation technique effectively suppress the dark current originating from the mesa sidewall of the Ge0.95Sn0.05 on Si (Ge0.95Sn0.05/Si) p-i-n photodiode. Current-voltage (I-V) characteristics show that the sidewall surface passivation technique could reduce the surface leakage current density (Jsurf) of the photodiode by ~100 times. A low dark current density (Jdark) of 0.073 A/cm2 at a bias voltage of −1 V is achieved, which is among the lowest reported values for Ge1-xSnx/Si p-i-n photodiodes. Temperature-dependent I-V measurement is performed for the Si-passivated and non-passivated photodiodes, from which the activation energies of dark current are extracted to be 0.304 eV and 0.142 eV, respectively. In addition, the optical responsivity of the Ge0.95Sn0.05/Si p-i-n photodiodes to light signals with wavelengths ranging from 1510 nm to 1877 nm is reported.

Investigation of stability and reliability of tin oxide thin-film for integrated micro-machined gas sensor devices

Abstract: The stability and reliability of SnO 2 /Pt, SnO 2 –Cu/Pt and SnO 2 /Pt/SnO 2 /Pt sensitive thin-films used for CO gas sensor device are discussed in this paper. The stability and reliability are very important for the tin dioxide-based gas sensor devices when these devices are to be integrated with standard CMOS circuitry. The drift in output voltage of tin dioxide sensing thin-film device must be minimized. The stability in the output of the tin dioxide thin-film sensing resistor is very essential to implement reliable integrated sensor device, because a small drift in baseline led to large change in the biasing current in the subsequent signal processing circuit. Here, we define the baseline as the output voltage across the two-terminal sensor in the absence of the signal. Another important parameter is the sensitivity of the sensor. The sensitivity of the device should be repeatable over large number of operation cycles. The drift in baseline and sensitivity of devices which are fabricated using SnO 2 /Pt, SnO 2 –Cu/Pt and SnO 2 /Pt/SnO 2 /Pt sensitive thin-films as gas sensitive material were studied. The sensor device based on SnO 2 –Cu/Pt thin-film shows good sensing characteristics. It was observed that the tin dioxide thin-film cracks during large number of operation cycles. The annealing of these thin-film at higher temperature or longer time induced the cracks in the sensing thin-film. These cracks are responsible for the drift in baseline and sensitivity of the thin-film. The cracks change the resistivity of the sensitive thin-film, which directly impact the device performance and reliability of the device. Our result shows, that SnO 2 –Cu/Pt thin-film is more stable as compared to SnO 2 /Pt and SnO 2 /Pt/SnO 2 /Pt thin-film. The change in surface structure during the operation of device was investigated using SEM technique. The accelerated thermal tests on the devices were performed to estimate the lifetime and evaluate the stability of the sensor device.