Chemical sensing and “non-sensing” in nitride heterostructures

The photoluminescence of InGaN/GaN semiconductor quantum wells is sensitive to the sub-surface electric field through quantum confined Stark effect (QCSE), which in turn depends on the adsorbed polar molecules on the semiconductor surface. Therefore a durable chemical sensor of gases, acidity or even trace concentration of biomolecules can be manufactured that is connected to a single optical fibre instead of metallic wires. During my six-month collaboration with the group of prof. Scholz at Ulm university, I investigated the potential sources of false-positive signal, showing that aside of chemical sensing, the quantum wells exhibit numerous unforeseen physical effects.