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This work reports on the development of a compact GaN high-electron-mobility transistor (HEMT) based biosensor for an easy and early detection of breast cancer biomarker C-erbB2 in the human cell line. The early-stage detection process includes a reaction of antibody-antigen through the cell line culture of a patient. The developed sensing chip has a two-finger gate structure of 125 µm gate width, and a gate length of 5 µm. In order to functionalize the gold surface of the fabricated sensor, the sensor chip has been immersed into an optimized 1 M aqueous solution of thioglycolic acid at room temperature for 15 h. Various characterization methods such as I–V, EDS, and FTIR confirm the formation of the Au–S complex. The functionalized sensors have been incubated in phosphate buffer saline solution of 200 µg ml−1 C-erbB2 monoclonal antibody for 4 h. Thereafter, the C-erbB2 monoclonal antibody conjugated devices are incubated with human cancer cells positive for C-erbB2 on its cell surface. The biosensor shows a 31% change in drain current for an incubation period of 6 h. The high-resolution biosensing chip (in terms of high drain current levels of the order of mA) is unaffected by noise and eases the circuit for futuristic point of care diagnostics.

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GaN/InGaN based violet light emitting diodes (LEDs), emitting at 430 nm, have been grown on conventional single side polished (SSP) and patterned sapphire substrates (PSS). Characteristics of the epitaxial wafers and subsequently fabricated LEDs have been analyzed. The photoluminescence (PL) peaks have been observed at 428.1 nm 426.1 nm for the epitaxial layers on SSP and PSS respectively. The PL intensity is 2.9 times higher in the case of PSS. The electroluminescence (EL) peaks have been observed at 430.78 nm and 430.35 nm for the LEDs on SSP and PSS respectively. The light output from LED fabricated on the PSS is 2.15 times higher than that of the LED on SSP at a forward current of 100 mA.