Design and Fabrication of AlGaN/GaN High Electron Mobility Transistors for Rapid Pathogen Detection

Ramelan, Ari Handono and Arifin, Pepen and , Sutarno (2010) Design and Fabrication of AlGaN/GaN High Electron Mobility Transistors for Rapid Pathogen Detection. IbM.

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    There has been significant recent interest in the use of surfacefunctionalized thin film and nanowire wide bandgap semiconductors, principally GaN, InN, ZnO and SiC, for sensing of gases, heavy metals, UV photons and biological molecules. For the detection of gases such as hydrogen, the semiconductors are typically coated with a catalyst metal such as Pd or Pt to increase the detection sensitivity at room temperature. Functionalizing the surface with oxides, polymers and nitrides is also useful in enhancing the detection sensitivity for gases and ionic solutions. The wide energy bandgap of these materials make them ideal for solar-blind UV detection, which can be of use for detecting fluorescence from biotoxins. The use of enzymes or adsorbed antibody layers on the semiconductor surface leads to highly specific detection of a broad range of antigens of interest in the medical and homeland security fields. We give examples of recent work showing sensitive detection of glucose, lactic acid, prostate cancer and breast cancer markers and the integration of the sensors with wireless data transmission systems to achieve robust, portable sensors. Semiconductor-based sensors can be fabricated using mature techniques from the Si chip industry and/or novel nanotechnology approaches. Silicon based sensors are still the dominant component of the semiconductor segment due to their low cost, reproducible and controllable electronic response. However, these sensors are not suited for operation in harsh environments, for instance, high temperature, high pressure or corrosive ambients. Si will be etched by some of the acidic or basic aqueous solutions encountered in biological sensing. By sharp contrast, GaN is not etched by any acid or base at temperatures below a few hundred degrees. Therefore, wide band-gap group III nitride compound semiconductors (AlGaInN materials system) are alternative options to supplement silicon in these applications because of their chemical resistance, high temperature/high power capability, high electron saturation velocity and simple integration with existing GaN-based UV light-emitting diode, UV detectors and wireless communication chips. A promising sensing technology utilizes AlGaN/GaN high electron mobility transistors (HEMTs). HEMT structures have been developed for use in microwave power amplifiers due to their high two-dimensional electron gas (2DEG) mobility and saturation velocity. The conducting 2DEG channel of AlGaN/GaN HEMTs is very close to the surface and extremely sensitive to adsorption of analytes. HEMT sensors can be used for detecting gases, ions, pH values, proteins, and DNA. The GaN materials system is attracting much interest for commercial applications of green, blue, and UV light-emitting diodes (LEDs), laser diodes as well as high speed and high frequency power devices. Due to the wide-bandgap nature of the material, it is very thermally stable, and electronic devices can be operated at temperatures up to 500°C. The GaN-based materials are also chemically stable, and no known wet chemical etchant can etch these materials; this makes them very suitable for operation in chemically harsh environments. Due to the high electron mobility, GaN material based high electron mobility transistors (HEMTs) can operate at very high frequency with higher breakdown voltage, better thermal conductivity, and wider transmission bandwidths than Si or GaAs devices. An overlooked potential application of the GaN HEMT structure is sensors. The high electron sheet carrier concentration of nitride HEMTs is induced by piezoelectric polarization of the strained AlGaN layer in the hetero-junction structure of the AIGaN/GaN HEMT and the spontaneous polarization is very large in wurtzite Ill-nitrides. This provides an increased sensitivity relative to simple Schottky diodes fabricated on GaN layers or field effect transistors (FETs) fabricated on the AIGaN/GaN HEMT structure. The gate region of the HEMT can be used to modulate the drain current in the FET mode or use as the electrode for the Schottky diode. A variety of gas, chemical and health-related sensors based on HEMT technology have been demonstrated with proper surface functionalization on the gate area of the HEMTs, including the detection of hydrogen, mercury ion, prostate-specific antigen (PSA), DNA, and glucose.

    Item Type: Article
    Subjects: Q Science > QH Natural history > QH301 Biology
    Divisions: Lembaga Penelitian dan Pengabdian Kepada Masyarakat - LPPM
    Depositing User: Lia Primadani
    Date Deposited: 15 Apr 2014 00:38
    Last Modified: 15 Apr 2014 00:38

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