Volume 92, Issue 1, 01 July 2002
Index of content:
- DEVICE PHYSICS (PACS 85)
92(2002); http://dx.doi.org/10.1063/1.1481973View Description Hide Description
Microscopic electroluminescence(EL) and photoluminescence (PL) measurements of high-biased AlGaN/GaN high-electron-mobility transistors are reported. We observed that the EL intensity reveals peaks around the edge of the channel and the electron temperature there is higher than the electron temperature at the center of the channel. These EL features were found to be consistent with the change in the junction temperature, which we locally estimated by comparing the PL data with measurements in raised ambient temperatures.
92(2002); http://dx.doi.org/10.1063/1.1481778View Description Hide Description
We present a simulation of a chain of three quantum cellular automaton (QCA) cells defined in a GaAs/AlGaAs heterostructure by means of depletion gates, focusing on the evaluation of the voltage unbalance that must be applied to the gates to enforce the correct polarization of the driver cell and propagate it through the other two cells. We use the configuration interaction method in each cell, including the electrostatic coupling between cells with an iterative self-consistent procedure. In particular, we investigate the issue, addressed in the recent literature, of chain malfunction due to the adverse effect on the driven cells of the electric field from the gates defining the driver cell. Our conclusion is that, as long as the gate voltage unbalance polarizing the driver cell is smaller than a threshold depending on geometric and material parameters, correct operation of the QCA wire can be obtained.
92(2002); http://dx.doi.org/10.1063/1.1480479View Description Hide Description
We investigate the detection of magnetic data using magnetooptical indicators with in-plane magnetization. A simple model for the magnetooptical detection system is presented. We find that the signal to noise ratio changes strongly with the bit size, the polarization noise, and the distance between the magnetic carrier and the indicator. In particular, it is found that our model a signal to noise ratio of 30 is possible for a bit size of 200 nm. We also estimate the resolution of the system, and find that a spot size of ∼200 nm can be obtained using a suitably designed solid immersion lens. Finally, we discuss detection of several magnetic tracks simultaneously.