Open-Gated pH Sensor Fabricated on an Undoped-AlGaN/GaN HEMT Structure

Abidin, Mastura Shafinaz Zainal; Hashim, Abdul Manaf; Sharifabad, Maneea Eizadi; Rahman, Shaharin Fadzli Abd; Sadoh, Taizoh

doi:10.3390/s110303067

Cited by 44 publications

(29 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Over the past decade, much attention has been paid to germanium (Ge) and III-V semiconductor channels [ 2 , 3 ] as the candidates to fulfill such purposes. Interestingly, these materials can not only be used to fabricate high speed conventional CMOS, but also to fabricate new transistors with different operating principles, such as tunnel field effect transistor (FET) [ 4 ], and various kinds of functional devices, such as sensors [ 5 , 6 ], optical devices [ 7 ], detectors [ 8 , 9 , 10 ] and solar batteries [ 11 ]. As reported by Takagi et al [ 3 ], co-integration of these functional materials on Si platform seems to offer the present ULSIs with superb multi-functionalities.…”

Section: Introductionmentioning

confidence: 99%

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)

et al. 2013

Self Cite

View full text Add to dashboard Cite

We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl4:C3H8O2) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm−1 corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm−1 corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.

show abstract

Section: Introductionmentioning

confidence: 99%

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…The hydroxyl groups (POH) are formed with P sites at the native oxide surface when the sensitive area contacts the aqueous solutions. The density of the POH groups can be modulated by chemically absorbing H + and OH − ions; thus, the surface charge type and density depend on the type and the concentration of the ions in solution, which is a function of the solution pH value [11]. When the concentration of H + ions is higher than that of OH − ions, the solution presents acidity.…”

Section: Discussionmentioning

confidence: 99%

“…Besides, the additional sensitive membrane on the surface is not necessary for GaN-based ion sensors [8,9], which can save the process time and simplify processes’ complexity, therefore reducing the product cost. The sensitivity to the surface charge results in the a good application of these ion sensors as pH value monitors, which has been widely adopted by using the traditional AlGaN/GaN HEMTs [9,10,11]. …”

Section: Introductionmentioning

confidence: 99%

High Sensitive pH Sensor Based on AlInN/GaN Heterostructure Transistor

Yan

Son

Dai

et al. 2018

Sensors

View full text Add to dashboard Cite

The AlInN/GaN high-electron-mobility-transistor (HEMT) indicates better performances compared with the traditional AlGaN/GaN HEMTs. The present work investigated the pH sensor functionality of an analogous HEMT AlInN/GaN device with an open gate. It was shown that the Al0.83In0.17N/GaN device demonstrates excellent pH sense functionality in aqueous solutions, exhibiting higher sensitivity (−30.83 μA/pH for AlInN/GaN and −4.6 μA/pH for AlGaN/GaN) and a faster response time, lower degradation and good stability with respect to the AlGaN/GaN device, which is attributed to higher two-dimensional electron gas (2DEG) density and a thinner barrier layer in Al0.83In0.17N/GaN owning to lattice matching. On the other hand, the open gate geometry was found to affect the pH sensitivity obviously. Properly increasing the width and shortening the length of the open gate area could enhance the sensitivity. However, when the open gate width is too larger or too small, the pH sensitivity would be suppressed conversely. Designing an optimal ratio of the width to the length is important for achieving high sensitivity. This work suggests that the AlInN/GaN-based 2DEG carrier modulated devices would be good candidates for high-performance pH sensors and other related applications.

show abstract

“…Gallium (Ga)-based compound materials such as gallium oxynitride (GaON) [7][8][9], gallium nitride (GaN) [10], and gallium oxide (Ga 2 O 3 ) [11] are among the promising inorganic compound semiconductors that provide many advantages over other organic materials for electronic and optoelectronic device applications [12][13][14][15][16][17][18][19]. Graphene, a carbon allotrope, possesses high carrier mobility, exceeding 10 4 cm 2 /Vs, even at room temperature (RT) [20].…”

Section: Introductionmentioning

confidence: 99%

Seed/Catalyst-Free Growth of Gallium-Based Compound Materials on Graphene on Insulator by Electrochemical Deposition at Room Temperature

Wong¹,

Ali²,

Yasui³

et al. 2016

Nano Online

Self Cite

View full text Add to dashboard Cite

We report the growth of gallium-based compounds, i.e., gallium oxynitride (GaON) and gallium oxide (Ga 2 O 3) on multilayer graphene (MLG) on insulator using a mixture of ammonium nitrate (NH 4 NO 3) and gallium nitrate (Ga(NO 3) 3) by electrochemical deposition (ECD) method at room temperature (RT) for the first time. The controlling parameters of current density and electrolyte molarity were found to greatly influence the properties of the grown structures. The thicknesses of the deposited structures increase with the current density since it increases the chemical reaction rates. The layers grown at low molarities of both solutions basically show grain-like layer with cracking structures and dominated by both Ga 2 O 3 and GaON. Such cracking structures seem to diminish with the increases of molarities of one of the solutions. It is speculated that the increase of current density and ions in the solutions helps to promote the growth at the area with uneven thicknesses of graphene. When the molarity of Ga(NO 3) 3 is increased while keeping the molarity of NH 4 NO 3 at the lowest value of 2.5 M, the grown structures are basically dominated by the Ga 2 O 3 structure. On the other hand, when the molarity of NH 4 NO 3 is increased while keeping the molarity of Ga(NO 3) 3 at the lowest value of 0.8 M, the GaON structure seems to dominate where their cubic and hexagonal arrangements are coexisting. It was found that when the molarities of Ga(NO 3) 3 are at the high level of 7.5 M, the grown structures tend to be dominated by Ga 2 O 3 even though the molarity of NH 4 NO 3 is made equal or higher than the molarity of Ga(NO 3) 3. When the grown structure is dominated by the Ga 2 O 3 structure, the deposition process became slow or unstable, resulting to the formation of thin layer. When the molarity of Ga(NO 3) 3 is increased to 15 M, the nanocluster-like structures were formed instead of continuous thin film structure. This study seems to successfully provide the conditions in growing either GaON-dominated or Ga 2 O 3-dominated structure by a simple and low-cost ECD. The next possible routes to convert the grown GaON-dominated structure to either single-crystalline GaN or Ga 2 O 3 as well as Ga 2 O 3-dominated structure to single-crystalline Ga 2 O 3 structure have been discussed.

show abstract

Open-Gated pH Sensor Fabricated on an Undoped-AlGaN/GaN HEMT Structure

Cited by 44 publications

References 17 publications

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)

High Sensitive pH Sensor Based on AlInN/GaN Heterostructure Transistor

Seed/Catalyst-Free Growth of Gallium-Based Compound Materials on Graphene on Insulator by Electrochemical Deposition at Room Temperature

Contact Info

Product

Resources

About