Detection of oxidising gases using an optochemical sensor system based on GaN/InGaN nanowires

摘要

We report on an all-optical sensor system that employs GaN/InGaN nanowire heterostructures (NWH) as optochemical transducers. When exposed to ultraviolet light, such NWHs emit green luminesce light. This photoluminescence (PL) is intense and temperature stable, and persists up to transducer temperatures well beyond 200 ℃. When exposed to oxidizing gases such as O_3, NO_2, and O_2 the PL intensity decreases. At room temperature minimum detectable O_(3-), NO_(2-), and O_2-concentrations are 50ppb, 500 ppb and 100 ppm, respectively. Above their minimum detectable concentrations the O_3, NO_2 and O_2 responses increase in a quasi-logarithmic manner up to a temperature-dependent saturation level. It is shown that the observed features can be explained within a model of Langmuir adsorption and surface recombination.