The role of indium composition on thermo-electric properties of InGaN/GaN heterostructures grown by MOCVD

Thermo Electric (TE) properties of InGaN/GaN heterostructure with different Indium compositions grown by Metal Organic Chemical Vapour Deposition (MOCVD) are investigated. Room temperature thermoelectric studies reveals that increasing indium composition (from 6% to 19%) in the InGaN/GaN heterostructure lead to a decrease in Seebeck coefficient (S) due to sharpening of bandgap which in turn increases TE figure of merit. Seebeck coefficient, Power factor and Figure of Merit of the InGaN/GaN heterostructured thin films shows significant enhancement at higher temperature up to 420 K as compared to room temperature measurement. Promising results on the TE properties of as grown InGaN/GaN heterostructures were observed with Figure of Merit (ZT) value of 0.15 at 420 K for In0.19Ga0.81N sample. The results indicate that InGaN material system could be potentially imparted for high temperature TE devices.