GaN microcavity structure with dielectric distributed Bragg reflectors fabricated by using a wet-chemical etching of a (111) Si substrate

Abstract

GaN microcavity structure with SiO2∕ZrO2 dielectric distributed Bragg reflectors was fabricated by means of transferring an InGaN∕GaN multiple quantum well (QW) structure from the (111) Si substrate onto a sapphire carrier and wet-chemical etching of the substrate. A dip in the reflectivity spectrum of the microcavity structure is observed at a wavelength of 411nm indicating the cavity resonance mode. Also, the strong influence of the cavity on the QW photoluminescence has been observed. A sharp emission spectrum, with a linewidth of 3.5nm, occurs at a wavelength of 411nm coincided with the position of the cavity resonance mode.

Strong light-matter coupling in bulk GaN-microcavities with double dielectric mirrors fabricated by two different methods

“…This can be performed by laser lift-off from a sapphire substrate, 13,14 etching of SiC ͑Ref. 15͒ or silicon substrates, 16,18 or combination of grinding, polishing, and etching of a GaN substrate. 17 Strong light-matter coupling was not demonstrated in any of the above double dielectric MCs but we have recently reported a "double dielectric plus epitaxial" mirror MC fabricated using silicon substrate removal in which the strong coupling regime was verified at 5 K through angle-dependent reflectivity and transmission measurements.…”

“…11 There are a number of significant difficulties to overcome, however, in fabricating a high-quality double dielectric DBR III-nitride MC. The inclusion of the second, lower dielectric DBR requires removal of the substrate in order to access the underside of the active region [12][13][14][15][16][17][18] ͓apart from one demonstration using lateral overgrowth above a stripe patterned dielectric DBR ͑Ref. 19͔͒.…”

Strong light-matter coupling in ultrathin double dielectric mirror GaN microcavities

“…4 However, the inclusion of a second, lower dielectric DBR is challenging as it requires removal of the substrate in order to access the underside of the active region. [5][6][7][8][9][10] This can be performed by laser lift-off from a sapphire substrate, 5,6 plasma etching of a SiC substrate, 7 wet or dry etching of a silicon substrate, 8,10 or combination of mechanical grinding, chemomechanical polishing, and dry etching of a GaN substrate. 9 Strong coupling was not demonstrated in any of these double dielectric MCs.…”

( In , Ga ) N ∕ Ga N microcavities with double dielectric mirrors fabricated by selective removal of an (Al,In)N sacrificial layer

“…5,6 The so-called fully hybrid approach exploits the well-established properties of high-reflectivity dielectric DBRs for both upper and lower mirrors, and offers the potential for higher finesse MCs. [7][8][9][10] Fabricating a MC of this type requires accessing the underside of the active region by removal of the substrate and buffer layers. Laser lift-off ͑LLO͒ from a sapphire substrate, 7,8 plasma etching of a SiC substrate, 9 and wet chemical etching of a silicon substrate 10 have all been employed to achieve this.…”

“…[7][8][9][10] Fabricating a MC of this type requires accessing the underside of the active region by removal of the substrate and buffer layers. Laser lift-off ͑LLO͒ from a sapphire substrate, 7,8 plasma etching of a SiC substrate, 9 and wet chemical etching of a silicon substrate 10 have all been employed to achieve this. After substrate removal, further thinning of buffer layers is usually required to accurately define the desired cavity length, and it is essential to have a reliable method to achieve this objective.…”