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Resistance-free charge spreading for LEDs and solar cells

Project description

Solid-state lighting and solar energy: lowering resistance, enhancing competitiveness

Electronic devices produce heat caused by resistance of components to current flow. This heat impacts device functioning – it is the reason your computer has a fan. When it comes to devices such as LEDs, lasers and solar cells, the loss in efficiency is significant and a major challenge for the lighting and solar energy markets. The EU-funded ZeroR project is tackling this issue by moving the so-called active region from a more internal position in the device to the device surface or, at least, limiting the expanse of the active region to minimise its heat effects on the device function. Success will boost European competitiveness in the solid-state lighting and solar energy harvesting sectors.


Joule heating due to electrical resistance associated with current spreading in semiconductors is a significant loss mechanism in modern state-of-the-art high power light emitting diodes (LEDs) and high concentration solar cells. These losses can account for up to 10-30 % of the device power consumption under high power conditions, and thereby dramatically reduce the efficiency of solar energy harvesting and general lighting, whose efficiencies – apart from the resistive losses – are gradually closing in on their theoretical limits. In ZeroR we make use of a conceptually simple but functionally dramatic modification to the previous buried active region (AR) devices, like LEDs, lasers and solar cells, by relocating the AR to outside the pn-junction, allowing e.g. locating the AR on the device surface – or locating all the contact structures fully on one side of the active region, eventually enabling a fully scalable and essentially resistance free structures. We analyze the commercial prospects of the technology and show that it provides new freedom for high power semiconductor device design. The main goal of ZeroR is to facilitate further commercial development of the concept and to demonstrate the elimination of resistive losses in industrially relevant LED and solar cell prototypes using gallium nitride and gallium arsenide based compound semiconductor material systems. If successful, this approach can substantially increase the device efficiency at selected high power operating conditions and substantially expedite the ongoing solid state lighting revolution and market penetration, also providing more efficient new solutions for solar energy harvesting and selected other applications.



Net EU contribution
€ 150 000,00
Otakaari 1
02150 Espoo

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Manner-Suomi Helsinki-Uusimaa Helsinki-Uusimaa
Activity type
Higher or Secondary Education Establishments
Other funding
€ 0,00

Beneficiaries (1)