SnOx thin films with tunable conductivity for fabrication of p–n homo‐junction

Tin oxide (SnOx) has been widely used for the fabrication of transparent and flexible devices because of its excellent optical and electronic properties. In this work, we established a methodology for the synthesis of SnOx thin films with p‐type and n‐type tunable conductivity by direct currecnt (DC) magnetron sputtering. The SnOx thin films changed from p‐type to n‐type by increasing the relative oxygen partial pressure (ppO2) from 4.8% to 18.5% and by varying the working pressure between 1.8 and 2.5 mTorr. The SnOx thin films were annealed at 160°C, 180°C, and 200°C for 30 min to promote the formation of the desired crystalline structures. At the annealing temperature of 180°C in air ambient, the SnOx thin films showed a tetragonal structure with Sn traces. Having found the optimal conditions, we deposited both types of SnOx thin films with the same tetragonal structure and similar chemical stoichiometry. Also, the conditions to obtain thin films with the highest mobility values for p‐type (1.10 cm2/Vs) and n‐type (22.20 cm2/Vs) were used for fabricating the device. Finally, the implementation of a SnOx‐based p–n diode was demonstrated using transparent SnOx thin films developed in this work, illustrating their potential use in transparent electronics.