Now showing 1 - 3 of 3
  • Publication
    Nanomanipulation of Functionalized Gold Nanoparticles on GaN
    ( 2023-01-01)
    Che Seliman M.A.
    ;
    Ali Yusup N.A.
    ;
    Ahmad M.A.
    ;
    Ibau C.
    ;
    ;
    Kawarada H.
    ;
    Hassan Z.
    ;
    Packeer F.
    ;
    Falina S.
    ;
    Syamsul M.
    Gold nanoparticles (AuNPs) are known for their high surface area to volume ratio, which acts as an excellent receptor when placed in between electrodes in sensor applications. Microelectrodes with bar and needle-shaped pointed ends in two configurations, comb and castle wall, were designed to be used for the fabrication of electrodes to observe the relation between the geometry of electrodes and the dielectrophoretic behaviour of AuNPs on p-gallium nitride (p-GaN) substrates. The electrical properties were analyzed before and after the drop cast of AuNPs using current-voltage (I-V) curve method with manual probing. Resistance values of each sample were calculated under reverse bias condition. The effect of the design configurations of the electrodes on the nanomanipulation of AuNPs will be discussed.
  • Publication
    Electrical Properties of GaN Cap Layer for AlGaN/GaN HEMT
    ( 2023-01-01)
    Hamid M.H.A.
    ;
    Asri R.I.M.
    ;
    ;
    Inaba M.
    ;
    Hassan Z.
    ;
    Kawarada H.
    ;
    Falina S.
    ;
    Syamsul M.
    Metal organic chemical vapor deposition (MOCVD) was used to grow AlGaN/GaN HEMT on a sapphire substrate with a 3.0 nm GaN cap and a sample without a GaN cap. High resolution Xray diffraction (HRXRD) was utilized to investigate the structural characteristics of the materials. The relationship between the electrical properties and two-dimensional electron gas (2DEG) I-V and Hall Effect measurement. The I-V measurement was used to investigate the resistance properties of AlGaN/GaN heterostructures. Hall Effect measurement was used to quantify electron mobility and sheet carrier concentration in both samples. The sample with a 3.0 nm GaN cap exhibited excellent electrical properties with 436.8 Ω/sq sheet resistivity and possessed a high value of sheet carrier concentration 3.46E+14 per cm2.
      1  18
  • Publication
    High-sensitivity room temperature p-doped and undoped GaN thin film resistive gas sensor
    ( 2022-01-01)
    Hasnan M.
    ;
    Asri R.I.M.
    ;
    Hassan Z.
    ;
    Abdalmohammed S.A.A.
    ;
    ;
    Inaba M.
    ;
    Falina S.
    ;
    Syamsul M.
    The behaviour and performance of p-doped GaN and undoped GaN thin film in the presence of methanol gas were studied. GaN thin films were grown using metal organic chemical vapour deposition (MOCVD), which were then fabricated into resistive sensors. Gas-sensing characterisation with the in-house gas chamber demonstrates that the resistive sensors based on undoped and p-doped GaN exhibit high sensitivity and fast response to methanol vapour in less than a minute, as well as excellent stability in room temperature operations. Without high temperature measurements, both undoped and p-doped GaN resistive sensors exhibit significant resistance variation and response over time when exposed to methanol, albeit with distinct properties. Here we demonstrate the comparison between the two and their sensing capabilities of both p-doped GaN and undoped GaN thin film resistive sensors.
      1  14