Vertical InGaN-based green-band solar cells operating under high solar concentration up to 300 suns

Abstract

InGaN/GaN-based solar cells with vertical-conduction feature on silicon substrates were fabricated by wafer bonding technique. The vertical solar cells with a metal reflector sandwiched between the GaN-based epitaxial layers and the Si substrate could increase the effective thickness of the absorption layer. Given that the thermally resistive sapphire substrates were replaced by the Si substrate with high thermal conductivity, the solar cells did not show degradation in power conversion efficiency (PCE) even when the solar concentrations were increased to 300 suns. The open circuit voltage increased from 1.90 V to 2.15 V and the fill factor increased from 0.55 to 0.58 when the concentrations were increased from 1 sun to 300 suns. With the 300-sun illumination, the PCE was enhanced by approximately 33% compared with the 1-sun illumination.

Evaluating different upscaling approaches to derive the actual power of distributed PV systems

“…As a result, recent reports on high efficiency InGaN solar cells have been focusing on surface roughening (textured surface) rather than structures with smooth surface and substrate. [11][12][13][14] Other optoelectronic devices have been more inclined to employ pattern sapphire substrates (PSS) to enhance light extraction. [18][19][20][21][22] Furthermore, despite costly and complicated growth and fabrication process, there have been reports proposing using diffraction grating on the back of the device for InGaN solar cells to enhance the optical absorption, 23 which combines the textured surface and reflecting substrate.…”

Analysis of loss mechanisms in InGaN solar cells using a semi-analytical model

“…As a result, recent reports on high efficiency InGaN solar cells have been focusing on surface roughening (textured surface) rather than structures with smooth surface and substrate. [11][12][13][14] Other optoelectronic devices have been more inclined to employ pattern sapphire substrates (PSS) to enhance light extraction. [18][19][20][21][22] Furthermore, despite costly and complicated growth and fabrication process, there have been reports proposing using diffraction grating on the back of the device for InGaN solar cells to enhance the optical absorption, 23 which combines the textured surface and reflecting substrate.…”

Vertical GaN-Based LEDs With Naturally Textured Surface Formed by Patterned Sapphire Substrate With Self-Assembled Ag Nanodots as Etching Mask

“…An InGaN top layer heavily doped with Si was also grown on the p-GaN contact layer [18]. After epitaxial growth, a bilayered Ni/Ag (1/200 nm) was deposited onto the p-GaN top layer to serve as a reflector/ohmic contact layer for the device [19]. After the formation of the reflector layer, a diffusion barrier consisting of a 200-nm-thick TiW layer and a 50-nm-thick Pt layer was deposited between the reflector and bonding layers.…”