Fabrication and optical characterization of GaN quasi-phase matching crystal by double polarity selective area growth in metal organic vapor phase epitaxy

Abstract

The fabrication of ultra-violet (UV) second-harmonic generation (SHG) (UV-SHG) devices requires GaN quasi-phase matching (GaN-QPM) crystals with periodically arranged polar GaN. For fabricating GaN-QPM crystals, the double polarity selective area growth (DP-SAG) using carbon mask technique is employed. However, the growth of narrow (2–4 [Formula: see text]m) pitch pattern GaN-QPM crystals, which is necessary for UV-SHG devices, has not been reported using this technique. Herein, we report the successful fabrication of 4 [Formula: see text]m pitch pattern GaN-QPM. We fabricated a thick GaN-QPM crystal at the optimized V/III ratio. Through optical characterization, we observed SHG generation from the GaN-QPM crystal fabricated using DP-SAG.

Fabrication and evaluation of rib-waveguide-type wavelength conversion devices using GaN-QPM crystals

“…Further, wavelength conversion has been demonstrated using a 4 μm period GaN-QPM crystal. 36) However, the SHG conversion efficiency, in this case, was relatively low owing to the short light transmission distance caused by the oblique incident measurement system. In this study, to improve the SHG conversion efficiency, we fabricated rib-waveguidetype wavelength conversion devices using GaN-QPM crystals.…”

“…We have previously proposed a simple technique for fabricating the GaN-QPM structure, the so-called doublepolarity selective-area growth (DP-SAG) method, in which a carbon mask is used. [33][34][35][36] The carbon mask enables the selective-area growth of GaN, and it can be removed in situ using ammonia (NH 3 ) gas. Thus, DP-SAG can be achieved without the sample loading out from the growth chamber.…”

Second harmonic generation in GaN transverse quasi-phase-matched waveguide pumped with femtosecond laser

“…A conventional longitudinal quasi-phase-matched (QPM) structure with periodic polarity inversion domains along the wave propagation direction is used for achieving high-efficiency wavelength conversion. [7][8][9][10][11] In the nitride semiconductors without ferroelectric nature, the formation of the polarity inverted structure requires crystal growth utilizing the controllability of crystallographic orientation. [12][13][14][15][16] However, the difference in growth rate between (0001) Ga-polar GaN (+c-GaN) and (0001 ¯) N-polar GaN (−c-GaN) makes it difficult to fabricate short-period longitudinal QPM structures.…”