GaN/InGaN based Blue LEDs and Solar cells

Under CSIR-TAPSUN programme, an improved design by incorporating ITO/ graphene as current spreading layers was carried out forenhancement of light extraction. LED epilayer structures having 9 and 10 QWs with or without strain-releasing superlattice (SL) structures weregrown on the single side polished (SSP), double side polished (DSP) and patterned sapphire substrates (PSS) by MOCVD and characterised.Preliminary vertical LEDs (VLEDs) were also fabricated after removing the sapphire substrate using laser lift-off (LLO) technique. Furtherworks would be continued to improve the performance of VLEDs.

The second batch of GaN/InGaN solar cell was fabricated on a p-i(15QW)-n epitaxial wafer and its characteristics were measured under 1 sun illumination at 25 °C under a CSIR network programme (D-NEED). The cell efficiency of 0.20 % was achieved compared to the first batch efficiency of 0.0015%.