Optimization of (In)GaN Heterostructures for Sensing Applications

Abstract

Herein, the optimization of (In)GaN heterostructures for chemical sensing is presented. The metalorganic vapor phase epitaxy (MOVPE)‐grown sensor consists of an InxGa1−xN quantum well (QW) placed close to the surface of a GaN substrate with a thin GaN cap layer on top. The photoluminescence (PL) wavelength of this QW is sensitive to surface potential changes and thus its optical signal is used as sensor response. Simulations are performed with nextnano to improve its sensitivity. Sensor parameters such as the cap layer thickness d, QW thickness Lz, background buffer layer doping concentration N, and indium concentration x of the QW are varied. It is found that a thin cap layer, together with high background doping and medium QW thickness, is ideal. The indium content does not show a strong influence on sensitivity. The trends found in the simulations are mostly confirmed in real‐world experiments performed in a chemical sensing setup, yet quantitative deviations exist.