High reflectivity airgap distributed Bragg reflectors realized by wet etching of AlInN sacrificial layers

Abstract

The authors report on the achievement of a vertically oriented three pair airgap/GaN distributed Bragg reflector realized by controlled oxidation and wet-chemical etching of AlInN sacrificial layers. Microreflectivity measurements exhibit high peak reflectivity values of 87% around 500 nm after the oxidation process and 90% around 600 nm after the etching process in overall good agreement with simulations. The broad stopband of airgap/GaN mirrors, about 250 nm wide, results from the strong refractive index contrast between air and GaN layers.

Dielectric function and optical properties of Al-rich AlInN alloys pseudomorphically grown on GaN

“…LM Al 1−x In x N has also a great potential for the application in highly-reflecting distributed Bragg reflectors (DBRs), light-emitting diodes (LEDs), laser diodes (LDs), detectors and sensors [6,7,8,9,10]. Recently, high reflectivity airgap distributed Bragg reflectors were fabricated by wet eching of LM AlInN sacrificial layers [11,12,13] and microdisk (µ-disk) technology, which is used for the new advanced devices, was developed [14]. In the work of Watson et al it was demonstrated that the additional insertion of LM AlInN layer into IIInitride multilayer structures grown on free-standing GaN substrate facilitates the in situ reflectence measurements, which allow accurate controll of layer thicknesses [15].…”

One-dimensional photonic crystals: fabrication, responsiveness and emerging applications in 3D construction

“…Since the early introduction of LBL deposition, 65 it becomes an important method for making 1DPCs. 61 Many other methods including chemical vapor deposition (CVD), physical vapor deposition (PVD) and molecular beam epitaxy are also utilized to build 1DPCs. 66 Very thin films of several nanometer with opposite charge are alternately deposited by repeating the sample immersion between the deposition and rinsing solutions.…”

“…2c), 42 while wet-chemical etching can be used to destroy a sacricial layer to form air/ GaN layer stacks. 61 Many other methods including chemical vapor deposition (CVD), physical vapor deposition (PVD), and molecular beam epitaxy have been also utilized to build 1DPCs. [69][70][71]…”

“…56 Besides the traditional organic and inorganic building platform we described above, new materials never stop emerging, such as liquid crystals, 57,58 zeolites, 59,60 and semiconductors. 61 Looking for more stable and multifunctional materials to build such structures will broaden the application elds of 1DPCs for practical use.…”

“…Basic optical property and Clay is chosen for it is low-cost, low-toxicity and easy to prepare. 61 Seeking for more stable and multifunctional material to build such structure will broaden the application fields of 1DPCs in practical use. [46][47][48] Similar to inorganic materials, polymers are also good choice for preparing 1DPCs for their responsiveness to diverse external stimuli through various kinds of functional groups.…”