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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Femtosecond laser micromachining of GaN using different wavelengths from near-infrared to ultraviolet

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Author(s):
Nolasco, L. K. [1, 2] ; Almeida, G. F. B. [3] ; Voss, T. [4, 5] ; Mendonca, C. R. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13561970 Sao Carlos, SP - Brazil
[2] Univ Sao Paulo, Sch Engn Sao Carlos, Dept Mat Engn, POB 359, BR-13563120 Sao Carlos, SP - Brazil
[3] Univ Fed Uberlandia, Inst Phys, POB 593, BR-38400902 Uberlandia, MG - Brazil
[4] Tech Univ Carolo Wilhelmina Braunschweig, Inst Semicond Technol, Hans Sommer Str 66, D-38106 Braunschweig - Germany
[5] Tech Univ Carolo Wilhelmina Braunschweig, Lab Emerging Nanometrol LENA, Langer Kamp 6, D-38106 Braunschweig - Germany
Total Affiliations: 5
Document type: Journal article
Source: Journal of Alloys and Compounds; v. 877, OCT 5 2021.
Web of Science Citations: 0
Abstract

This paper presents a study on the incubation effect during fs-laser micromachining of gallium nitride films with three different wavelengths (1030, 515 and 343 nm) by varying the number of laser pulses applied per sample surface area and measuring the damage threshold fluence using the zero damage method. As we implemented the exponential defect accumulation model to the experimental incubation data, we determined the value of the incubation parameter of (0.02 +/- 0.01) for 1030 nm, (0.07 +/- 0.01) for 515 nm and (0.4 +/- 0.1) for 343 nm. This shows that for excitation in the green and infrared spectral region, GaN requires approximately 100 overlapping pulses in order for the incubation to take place while, for ultraviolet excitation, the incubation was achieved faster, with the overlap of about 10 pulses. Furthermore, we compared our data for the single pulse damage threshold with a theoretical model that takes into account multi photon and avalanche ionization. Our results indicate that at 343 nm and 515 nm, micromachining is dominated by multiphoton ionization, while at 1030 nm other effects, such as tunneling ionization, must also be contributing. Finally, we believe this paper brings relevant information on the fs-laser micro machining of GaN. (c) 2021 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 18/11283-7 - Nonlinear photonics: spectroscopy and advanced processing of materials
Grantee:Cleber Renato Mendonça
Support Opportunities: Research Projects - Thematic Grants