Field emission from GaN surfaces roughened by hydrogen plasma treatment

Sugino, Takashi; Hori, Takamitsu; Kimura, Chiharu; Yamamoto, T.

doi:10.1063/1.1370979

Cited by 79 publications

(53 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar results were also observed on NW samples with rough surfaces. 17,[23][24][25] In the growth process of GaN NWs with nanoscale protrusions, it is expected that the Ga vapor reacts with the N vapor, which is decomposed from the NH 3 at a high temperature of 950°C to form the GaN structure. It has been reported that hydrogen has a higher surface mobility and can stream easier and faster than the products of GaN molecules.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Nanoscale Protrusions on Field-Emission Properties for GaN Nanowires

Lee

Shin

Chen

et al. 2007

J. Electrochem. Soc.

View full text Add to dashboard Cite

GaN nanowires ͑NWs͒ have been synthesized on platinum-coated silicon͑111͒ substrates by the chemical vapor deposition ͑CVD͒ method under different NH 3 /H 2 carrier gas-flow rate ratios. X-ray diffractometer and transmission electron microscope analyses indicate that GaN NWs have wurtzite structures. Nanoscale protrusions with crystal orientation along the ͓002͔ direction were observed on the surface of GaN NWs grown under high H 2 flow rate conditions. As compared to the field-emission result of GaN NWs with smooth surfaces, GaN NWs with nanoscale protrusions exhibit a lower turn-on field of 8.5 V/m and a higher field-enhancement factor of ␤ = 315. These nanoscale protrusions are believed to account for the enhancement of the fieldemission behaviors of GaN NWs. Gallium nitride ͑GaN͒ has a wide direct bandgap of 3.4 eV at room temperature and is a popular semiconductor material with potential applications in blue and UV light emission, high temperature, and high power electronic devices.1,2 Recent efforts have been devoted to carbon nanotubes ͑CNTs͒ and ZnO nanostructures to improve the performance of conventional Spindt-type Mo field emitters. Because Mo, CNTs, and ZnO have a work function around 4.5 eV, sharp needlelike nanostructures are required to enhance electron emission with sufficient current density. GaN has attractive properties as a material for field emitters, e.g., a lower work function ͑4.1 eV͒ and stronger chemical and mechanical stability than those listed above. These properties make it a desired alternative material for field emitters. Typical GaN nanostructure morphologies include nanowires ͑NWs͒, nanorods, nanobelts, and nanotubes. Recently, needlelike 3 structures and quasi-aligned 4 GaN NWs have been grown and studies have shown that the sharp tip is responsible for the enhancement of the field-emission ͑FE͒ properties of NWs. The resulting turn-on field is ϳ7.5 V/m for needlelike 3 GaN NWs and ϳ7.0 V/m for quasi-aligned 4 GaN NWs. In these studies, the electrons were emitted from the tip of the NW due to its high aspect ratio. The FE characteristics of various GaN NWs created from different synthesizing methods are listed in Table I. All the GaN NWs listed in this table were grown under a constant flow rate of NH 3 . However, no study has ever been performed with different carrier gases, such as H 2 . This report not only shows the effect of different NH 3 /H 2 flow rate ratios on the growth and FE properties but also demonstrates the ability to use platinum as the catalyst for GaN NW growth of many other transition metals, such as Fe, Co, Ni, and Au. Nanoscale protrusions with crystal orientation along the ͓002͔ axis were first observed on the surface of GaN NWs that were grown under high H 2 flow rate conditions. The correlation between the FE behaviors and nanoscale protrusions were also explored in this report. ExperimentalGaN NWs were grown by thermally reacting metallic Ga ͑3 g͒ with different ratios of NH 3 /H 2 gases at 950°C for 30 min. In a horizontal quartz-tube furnace with a ...

show abstract

Section: Resultsmentioning

confidence: 99%

The Effect of Nanoscale Protrusions on Field-Emission Properties for GaN Nanowires

Lee

Shin

Chen

et al. 2007

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…The previously reported turn-on electric field has ranged approximately between 7 and 133 V/μm for the GaN pyramid arrays and the roughened GaN surface [2][3][4][5], and between 1.25 and 40 V/μm for the GaN nanorod or nanocolumn films [6,7] although it is rather difficult to compare all of them under the same measurement conditions. On the other hand, the values of 1.5 × 10 2 [5] and 4.96 × 10 3 [7] have been reported as β'.…”

Section: Resultsmentioning

confidence: 96%

“…The field conversion factor β, estimated from the slope, ranges from 4.1-5.5 × 10 4 cm -1 using the electron affinity of 2.7-3.3 eV for GaN. Then, the field enhancement factor β' (= βd) is calculated to be 1.2-1.7 × 10 2 , where d is a spacing between the anode electrode and the emitter [5].…”

Section: Resultsmentioning

confidence: 99%

“…To this effect, the studies on the application of GaN for field emitters have been carried out concentrating on the formation of sharp tips [1][2][3][4][5][6][7]. The approaches developed so far are fabrication of array of pyramid-shape GaN by selective area growth [1][2][3][4], roughening the surface of GaN epilayer by plasma etching [5], spontaneous tip formation during columnar growth [6], and so on. Recently, the dramatic reduction in turn-on electric field has been achieved for the nanorod film grown on Si substrates with native oxides [7].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Fabrication of field emitters using GaN particles

Minakuchi

Neo

Mimura

et al. 2010

Phys. Status Solidi (c)

View full text Add to dashboard Cite

The field emission from GaN particles has been demonstrated successfully for the first time. The novel field emitting device has a simple structure consisting of an electrically conductive polymer layer and GaN particles spread randomly on it. The GaN particles used for this device, which were synthesized in advance by the two‐stage vapor phase method, have vertices and ridges formed by well‐developed crystal planes. The electron emission started at an electric field of about 20 V/μm, and the current reached 10 nA at 28 V/μm. The maximum current density was 0.26 mA/cm2at 43 V/μm. The Fowler‐Nordheim (F‐N) plot of the I ‐V data indicated that the observed electron emission is originated from the F‐N tunneling. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

show abstract

“…Actually, a low threshold voltage was obtained for the tip-like structure, which was formed by growth technique and plasma treatment for BN [8], AlN [9] and GaN [10] systems. Figure 2 shows an atomic force microscopy (AFM) image of the GaN surface grown on Mo substrates at 780 and 700 C. GaN on Mo has a preferential c-orientation and a grain structure.…”

mentioning

confidence: 99%