High-Electron-Mobility AlGaN/GaN Transistors (HEMTs) for Fluid Monitoring Applications

Neuberger, R.; Müller, Gerhard; Ambacher, O.; Stutzmann, M.

doi:10.1002/1521-396x(200105)185:1<85::aid-pssa85>3.0.co;2-u

Cited by 129 publications

(86 citation statements)

References 12 publications

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“…20 The large variation is probably related to various chemical contaminations of the surface layer, including adsorption of ionic species on the sample surface. 29 The sensitivity of the simulations to changes in the fitting parameters is illustrated in Fig. 6, for the case of the single Al 0.32 Ga 0.68 N/GaN heterostructure.…”

Section: Discussionmentioning

confidence: 99%

Polarization effects in AlGaN/GaN and GaN/AlGaN/GaN heterostructures

Heikman

Keller

et al. 2003

Journal of Applied Physics

210

130

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The influence of AlGaN and GaN cap layer thickness on Hall sheet carrier density and mobility was investigated for Al 0.32 Ga 0.68 N/GaN and GaN/Al 0.32 Ga 0.68 N/GaN heterostructures deposited on sapphire substrates. The sheet carrier density was found to increase and saturate with the AlGaN layer thickness, while for the GaN-capped structures it decreased and saturated with the GaN cap layer thickness. A relatively close fit was achieved between the measured data and two-dimensional electron gas densities predicted from simulations of the band diagrams. The simulations also indicated the presence of a two-dimensional hole gas at the upper interface of GaN/AlGaN/GaN structures with sufficiently thick GaN cap layers. A surface Fermi-level pinning position of 1.7 eV for AlGaN and 0.9-1.0 eV for GaN, and an interface polarization charge density of 1.6 ϫ10 13 -1.7ϫ10 13 cm Ϫ2 , were extracted from the simulations.

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Section: Discussionmentioning

confidence: 99%

Polarization effects in AlGaN/GaN and GaN/AlGaN/GaN heterostructures

Heikman

Keller

et al. 2003

Journal of Applied Physics

210

130

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“…PL intensity quenches under vacuum and decreases in dry environments, whereas it is maintained under water-vapor-containing atmospheres [11]. Features of molecules in the surroundings, such as molecular weight, polar character and size among others, have been suggested to be responsible for similar effects [18,19].…”

Section: Introductionmentioning

confidence: 99%

Photoexcited-induced sensitivity of InGaAs surface QDs to environment

Milla

Ulloa²,

Guzmán

2014

Nanotechnology

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A detailed analysis of the impact of illumination on the electrical response of In 0.5 Ga 0.5 As surface nanostructures is carried out as a function of different relative humidity conditions. The importance of the surface-to-volume ratio for sensing applications is once more highlighted. From dark-to-photo conditions, the sheet resistance (SR) of a three-dimensional In 0.5 Ga 0.5 As nanostructure decays two orders of magnitude compared with that of a two-dimensional nanostructure. The electrical response is found to be vulnerable to the energy of the incident light and the external conditions. Illuminating with high energy light translates into an SR reduction of one order of magnitude under humid atmospheres, whereas it remains nearly unchanged under dry environments. Conversely, lighting with energy below the bulk energy bandgap, shows a negligible effect on the electrical properties regardless the local moisture. Both illumination and humidity are therefore needed for sensing. Photoexcited carriers can only contribute to conductivity if surface states are inactive due to water physisorption. The strong dependence of the electrical response on the environment makes these nanostructures very suitable for the development of highly sensitive and efficient sensing devices.

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“…In addition to this, however, new trends are now emerging which indicate that III-V nanoelectronics may open up a greater future in much wider device application areas than today, combining information technology, nanotechnology and biotechnology all of which have recently made tremendous progress. Namely, on the main stream roadmap for high end processor applications, gigantic Si industries such as Intel corp. now seem to admit existence of the ultimate scaling limit of the Si CMOS technology, and III-V transistors such as AlInSb/InSb metal insulator semiconductor GaAs [16][17][18][19], GaN and AlGaN/GaN [20][21][22][23][24] materials. The device structures used in these sensors are Schottky diodes, open-gate (or gateless) field effect transistors (FETs) and ordinary FETs which are familiar in conventional transport devices.…”

Section: Introductionmentioning

confidence: 99%