The Structure and Ultraviolet Electroluminescence of n-ZnO-SiO₂-ZnO Nanocomposite/p-GaN Heterojunction LED

Abstract

Ultraviolet (UV) light-emitting diodes composed of n-ZnO:AlSiO 2 -ZnO nanocomposite/p-GaN:Mg heterojunction were fabricated on the c-plane sapphire substrate. TEM images clearly reveals a dispersion of high crystalline ZnO nanoparticles in the amorphous SiO 2 matrix with sizes about 3~10 nm. Analyses of the Zn distribution by means of EDX and HAADF show a strongly non-uniform distribution of Zn within the SiO 2 matrix. The SiO 2 -ZnO nanocomposite layer accomplishes a role of the current blocking layer and also causes, by its low refractive index, the increase in the light extraction efficiency from n-ZnO. With a SiO 2 layer, significant UV electroluminescence from n-ZnO was achieved at a low forward-bias current of 1.8 mA. Strong UV emission arising from impact ionization in GaN, ZnO, and GaN:Mg states was also observed at reverse breakdown bias.

ZnO-based ultra-violet light emitting diodes and nanostructures fabricated by atomic layer deposition

“…We would like to acknowledge great contributions of our collaborators, particularly, coauthors of the papers cited in [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], to the present investigations.…”

“…Over the last few years, we have investigated ZnObased UV LEDs and nanostructures fabricated by ALD, demonstrating that ALD is one of the noteworthy techniques to prepare high-quality ZnO required for these devices. Here, we review our electro-optical and structural investigations on ZnO films and nanostructures [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], which were performed using x-ray diffraction (XRD) and various electron microscopy techniques as well as spectroscopy analyses.…”

Study the compatibility between four detectors manufactured on one silicon chip

“…Quadrant detector operates in the visible light area and is used to manufacture solar trackers. The following equation represents the current flowing in the diode in the forward direction [10]:…”