| abstract |
Disclosed herein are p-n metal oxide semiconductor (MOS) heterostructure-based sensors and systems. The sensors and systems described herein can include sensing element that comprises a first region comprising a p-type MOS material (e.g., NiO) and a second region comprising an n-type MOS material (e.g., In 2 O 3 ). These sensors and systems can exhibit sensitivity and selectivity to NH 3 at ppb levels, while discriminating against CO, NO, or a combination thereof at concentrations a thousand-fold higher (ppm) and spread over a considerable range (0-20 ppm). These sensors and systems can be used to detect and/or quantify NH3 in samples, including biological samples (e.g., breath samples) and combustion gases. |