A simple physical metal mask is efficiently employed to obtain an array of silicon (Si) nanowires (Si-NWs) on a Si substrate grown using the hot filament chemical vapor deposition route. Well adhered and uniform coating of different thicknesses (20 and 50 nm) of lanthanum hexaboride (LaB6) on Si-NWs was obtained using electron beam evaporation technique. The thickness of LaB6 coating was estimated from ellipsometry measurement. Structural, morphological, and chemical properties of the LaB6 coated Si-NWs (LaB6@Si-NWs) arrays were revealed using x-ray diffraction, field emission scanning electron microscope, transmission electron microscope, Raman spectroscopy, and x-ray photoelectron spectroscopy. Field electron emission characteristics of pristine Si-NW array and LaB6 coated Si-NWs array emitters were studied in planar diode configuration at a base pressure of 1 × 10−8 mbar. The values of turn-on field (current density ∼1 μA/cm2) were observed as ∼2.2, 1.2, and 1.6 V/μm for pristine Si-NWs, LaB6@Si-NWs_20, and LaB6@Si-NWs_50 array emitters, respectively. Furthermore, maximum emission current densities of ∼1276.81, 2763.64, and 2231.81 μA/cm2 have been extracted from the pristine Si-NWs, LaB6@Si-NWS_20, and LaB6@Si-NWS_50 array emitters at an applied field of 3.1, 2.7, and 2.7 V/μm, respectively. The LaB6@Si-NWS_20 array emitter demonstrated superior FEE properties as compared to the pristine Si-NWs and LaB6@Si-NWS_50 emitters. Furthermore, LaB6@Si-NWS_20 emitter depicted very good emission current stability tested at a preset value of 1 μA over a duration of 3 h. The enhanced FEE performance exhibited by the LaB6@Si-NWs_20 array emitter is attributed to reduction in effective work function and enhanced electron tunneling probability across the LaB6–Si interface.
Thickness dependent field emission study of LaB6 coated Si nanowire arrays
Note: This paper is a part of the 2023 Special Topic Collection on Vacuum Nanoelectronics.
Amol Deore, Krishna Jagtap, Onkar Bhorade, Angela Vella, Mahendra More; Thickness dependent field emission study of LaB6 coated Si nanowire arrays. J. Vac. Sci. Technol. B 1 March 2023; 41 (2): 022806. https://doi.org/10.1116/6.0002464
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