Papers by Author: Jumiah Hassan

Abstract: A photoflash method of thermal diffusivity measurement was used to determine the value of thermal diffusivity of a sandwiched aluminum layer in a three-layer sample when the sample is simultaneously subjected to both thermal and electric field gradients. The value of the thermal diffusivity of the sample initially measured before electric field was applied agreed well with other reported results. The thermal diffusivity was also found to decrease or increase under the influence of the electric field strength or direction.

Abstract: The spark of aggressive scaling of transistors was started after the Moors law on prediction of device dimensions. Recently, among the several types of transistors, junctionless transistors were considered as one of the promising alternative for new generation of nanotransistors. In this work, we investigate the pinch-off effect in double gate and single gate junctionless lateral gate transistors. The transistors are fabricated on lightly doped (10¹⁵) p-type Silicon-on-insulator wafer by using an atomic force microscopy nanolithography technique. The transistors are normally on state devices and working in depletion mode. The behavior of the devices confirms the normal behavior of the junctionless transistors. The pinch-off effect appears at V_G +2.0 V and V_G +2.5 V for fabricated double gate and single structure, respectively. On state current is in the order of 10^-9 (A) for both structures due to low doping concentration. The single gate and double gate devices exhibit an I_on/Io_ff of approximately 10⁵ and 10⁶, respectively.

Abstract: In this work, we have investigated the fabrication of Double gate and Single gate Junctionless silicon nanowire transistor using silicon nanowire patterned on lightly doped (10⁵ cm^-3) p-type Silicon on insulator wafer fabricated by Atomic force microscopy nanolithography technique. Local anodic oxidation followed by two wet etching steps, Potassium hydroxide etching for Silicon removal and Hydrofluoric acid etching for oxide removal, were implemented to reach the structures. Writing speed and applied tip voltage were held in 0.6 µm/s and 8 volt respectively for Cr/Pt tip. Scan speed was held in 1.0 µm/s. The etching processes were elaborately performed and optimized by 30%wt. Potassium hydroxide + 10%vol. Isopropyl alcohol in appropriate time, temperature and humidity. The structure is a gated resistor turned off based on a pinch-off effect principle, when essential positive gate voltage is applied. Negative gate voltage was unable to make significant effect on drain current to drive the device into accumulation mode.

Abstract: Ni_0.4Zn_0.6Fe₂O₄-polypropylene (PP) composites were investigated for their dielectric property which constitutes the dielectric constant , and dielectric loss factor . Nickel zinc ferrites (NZF) were prepared via the conventional solid state method and sintered at 1250 °C for 10 hours. Ni_0.4Zn_0.6Fe₂O₄ acts as filler while PP is the matrix. 5% and 25% NZF were added into the PP and blended to form NZF-PP composites. Dielectric measurements were made from room temperature to 120 °C at 20 °C intervals using the HP 4284A Precision LCR Meter at frequencies 240 Hz to 1 MHz. is almost constant and independent of frequency and temperature below 100 KHz before decreasing showing dispersion probably due to space charge or interfacial polarization. Distinct relaxation loss peaks can be seen emerging at about 100 KHz shifting towards the higher frequency with increasing temperature. Generally, increasing the content of filler improve the dielectric strength of the composite. Thus, addition of NZF enhances the dielectric properties of NZF-PP composite.