BARC/PUB/2019/1073

 
 

Nanosecond laser induced surface micro-structuring of Tantalum targets for improved field emission

 
     
 
Author(s)

Singh, A. K.; Suryawanshi, S. R.; More, M. A.; Singh, K.; Sinha, S.
(L&PTD;L&PSPS;MSD)

Source

Materials Research Express, 2019. Vol. 6: Article no. 106418

ABSTRACT

In this paper we report our results on nanosecond laser based surface micro (μ)-structuring of Tantalum (Ta) samples and their field emission behavior. Surface micro-structuring has been carried out using a typical laser fluence of 0.9 J cm−2 and varying number of incident laser pulses in the range of 3000 to 9000. Laser treated samples have been characterized in terms of surface morphology, chemical phase and field emission behavior. Nanosecond laser irradiation resulted in formation of self assembled surface μ-protrusions in the laser treated region. Peak height of the generated μ-protrusions and average roughness of the laser treated region increased with increasing number of irradiating laser pulses. Laser treated specimens have shown enhanced field emission in comparison to pristine Ta specimen. Specimens μ-structured using 3000, 6000 and 9000 laser pulses per spot have shown field emission with turn on field (Eon) of 6.6 V−1 μm−1, 4.8 V −1 μm−1 and 3.7 V −1μm−1, respectively. Also, maximum emission current density delivered by these laser modified specimens was found to increase with increasing number of laser pulses. Although, Ta specimen μ-structured with 9000 laser pulses has shown highest emission current density, emission current stability of this sample was poorer in comparison to specimens modified using 3000 and 6000 laser pulses.

 
 
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