In Ga N ∕ Ga N nanostripe grown on pattern sapphire by metal organic chemical vapor deposition

Abstract

The authors have used metal organic chemical vapor deposition to grow InGaN∕GaN multiple quantum well (MQW) nanostripes on trapezoidally patterned c-plane sapphire substrates. Transmission electron microscopy (TEM) images clearly revealed that the MQWs grew not only on the top faces of the trapezoids but also on both lateral side facets along the [0001] direction defined by the selected area electron diffraction pattern. Meanwhile, dislocations that stretched from the interfaces between the GaN and the substrates did not pass through the MQWs in the TEM observation. Microphotoluminescence measurements verified that the luminescence efficiency from a single nanostripe was enhanced by up to fivefold relative to those of regular thin film MQW structures. Observation of the cathodoluminescence identified the areas of light emission and confirmed that enhanced emission occurred from the nanostripes.

Investigation on microstructure in GaN epitaxial growth on the stripe-patterned r-plane sapphire substrates

“…However, the multiple-step regrowth process is too complicated and time consuming. In addition to ELOG and PE, several groups have proposed that direct lateral epitaxial growth on patterned sapphire substrates (PSSs) can simplify the growth process and enhance device performance and efficiency [8][9][10][11]. In our previous work [11], we have demonstrated that GaN grown on patterned r-plane sapphire substrates with asymmetrically inclined facets can have a very low-defect density (10 7 cm À2 ) in GaN epilayers without regrowth process.…”

Evaluation of Lateral Ni Diffusion in Si Nanowire Schottky Contact

“…Commonly, metal silicide contacts, especially NiSi, have been used to reduce the resistance for bulk and SOI FET. However, the lateral diffusion of Ni to form NiSi in SiNW is still unknown (1)(2)(3)(4). In this paper, evaluation of lateral Ni diffusion into SiNW has been conducted.…”

Fabrication of nano-patterned sapphire substrates and their application to the improvement of the performance of GaN-based LEDs

“…Theoretical and experimental studies indicate that a further reduction in the defect density is possible if the lateral overgrowth approach is reduced to nano-scale [12,13]. Nanostructure devices may also play an important role in overcoming the existing dislocations and difficulties encountered in light extraction [14]. In this study, we describe the fabrication and characteristics of GaNbased LEDs on nano-patterned sapphire substrates (NPSSs) and demonstrate the enhancement of the light output power of LEDs on NPSSs over conventional LEDs on the planar sapphire substrate.…”