Synthesis of Well-Crystalline GaS Nanobelts and Their Unique Field Emission Behavior
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- 作者：Subhendu K. Panda ; Anuja Datta ; Godhuli Sinha ; Subhadra Chaudhuri ; Padmakar G. Chavan ; Sandip S. Patil ; Mahendra A. More ; Dilip S. Joag
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：April 24, 2008
- 年：2008
- 卷：112
- 期：16
- 页码：6240 - 6244
- 全文大小：313K
- 年卷期：v.112,no.16(April 24, 2008)
- ISSN：1932-7455
文摘
Well-crystalline ultrathin GaS nanobelts have been successfully synthesized on silicon substrates by a simplethermal evaporation process. The GaS nanobelts were examined by X-ray diffraction (XRD), scanning electronmicroscope (SEM), high-resolution transmission electron microscope (HRTEM), and energy dispersive X-rayanalysis (EDAX). The XRD pattern indicates formation of well-crystalline hexagonal phase GaS nanostructures.The SEM image shows uniformly distributed GaS nanostructures covering the entire substrate surface. TheTEM results reveal that the GaS nanostructures are "nanobelts" of widths 20 to 50 nm and lengths up toseveral microns, and some of them are L-shaped. The growth mechanism and formation of GaS straight andL-shaped nanobelts has been explained. The field emission studies revealed that the threshold field requiredto draw an emission current of ~1 nA is to be 2.9 V/
m, and a current density of ~5.7 A/cm2 can be drawnat an applied field of 6.0 V/m. The Fowler-Nordheim plot, derived from the observed current density-applied field characteristics depicts nonlinear behavior over the entire range of applied field. The fieldenhancement factor is estimated to be ~2.0 × 104. The emission current stability investigated over a durationof more than 2 h at the preset value ~4.0 A shows initial increment followed by stabilization to a highervalue ~6.0 A. The average emission current at the stabilized value is seen to be fairly constant with currentfluctuations within ±10%. The results suggest the use of GaS nanobelts as a promising electron source forapplications in field emission based devices.
m, and a current density of ~5.7 A/cm2 can be drawnat an applied field of 6.0 V/m. The Fowler-Nordheim plot, derived from the observed current density-applied field characteristics depicts nonlinear behavior over the entire range of applied field. The fieldenhancement factor is estimated to be ~2.0 × 104. The emission current stability investigated over a durationof more than 2 h at the preset value ~4.0 A shows initial increment followed by stabilization to a highervalue ~6.0 A. The average emission current at the stabilized value is seen to be fairly constant with currentfluctuations within ±10%. The results suggest the use of GaS nanobelts as a promising electron source forapplications in field emission based devices.