Near-surface GaN/GaInN quantum wells (QWs) were investigated as optical transducers for the detection of hydrogen sulfide. The heterostructure sensors were grown by metal organic vapor phase epitaxy and later covered by a thin layer of Au by electron beam evaporation. The QW photoluminescence (PL) is sensitive to changes in the sensor surface potential. By the adsorption of hydrogen sulfide (H 2 S) on the Au cover layer, downward near-surface band bending results in an increase of the quantum confined Stark effect in the GaInN QW producing a red shift in its luminescence. Unexpectedly, an increase in PL intensity is also observed. A concentration of 0.01 parts per million of H 2 S in nitrogen has been successfully detected. This phenomenon may be helpful to detect trace amounts of H 2 S present in the human breath for early detection of diseases.

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Accurate detection of gases such as hydrogen sulfide in the exhaled human breath is of great interest for medical professionals as it can possibly help in the early detection of organ malfunction and other diseases. GaInN heterostructure sensors are sensitive to the changes in the surface potential caused by the adsorption of gas molecules. A quantum well (QW) placed close to the surface experiences a change in the quantum‐confined Stark effect and as a result shifts its photoluminescence signal. Several parameters of the GaInN sensors grown by metal organic vapor phase epitaxy are optimized such as the GaN cap layer, QW thickness, and doping concentration. Moreover, how various metal functionalization layers can improve its sensitivity and selectivity is investigated. Gold (Au) and Silver (Ag) shows sensitivity to hydrogen sulfide in the 10–100 parts per billion (ppb) range. Ammonia gas is also detected in the 5–10 range (ppm) with a sensor structure covered with a thin gold layer.