The paper studies the performance of a gas sensor based on an organic/inorganic diode for ammonia (NH3) sensing under atmospheric conditions at room temperature and different humidity levels. The diode structure consists of a layer of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) deposited on top of n‐type GaAs. The PEDOT:PSS layer that is filled with different ratios of graphene oxide (GO) is prepared from the solution phase. We show that the current–voltage (I–V) response of­­­­­ the diode and the sensing performance improve significantly by adding GO to the PEDOT:PSS layer. The sensing response is highest for a diode with 0.04 wt.% of GO. At room temperature, the PEDOT:PSS:GO (0.04 wt.%)/n‐GaAs Schottky diode shows a sensitivity of 194 upon exposure to 20 ppm of NH3 with rapid response and recovery times between 95 and 121 s, respectively. The NH3 sensor based on PEDOT:PSS:GO is cost‐effective, environmentally friendly, and easy to fabricate using low‐cost solution‐processing methods.

The performance of a room‐temperature (300 K) ammonia (NH3) sensor is investigated in article no. http://doi.wiley.com/10.1002/pssr.201800037. The sensor is based on the organic/inorganic Schottky diode between poly (3,4‐ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS):graphene oxide (GO) and n‐type GaAs. GO sheets are mixed in different concentration with PEDOT:PSS water‐based suspensions. This composite is used as an ammonia sensing layer in the n‐GaAs Schottky diode. The diode parameters and sensing performance were improved via adding an infinitesimal amount of GO into PEDOT:PSS. The ammonia sensor is shown to have high sensitivity and fast response time to different NH3 concentrations. PEDOT:PSS:GO films have the potential to be used as a sensing layer material in Schottky diode‐based gas sensors that require high speed, high sensitivity, low power consumption, and excellent selectivity.