High Hall Mobility P‐type Cu 2 SnS 3 ‐Ga 2 O 3 with a High Work Function

A new transparent p‐type oxide semiconductor (POS) is reported, Cu 2 SnS 3 ‐Ga 2 O 3 , having high Hall mobility of 36.22 cm 2 V −1 s −1 , and high work function of 5.17 eV. The existence of Cu 2 SnS 3 and Ga 2 O 3 phases in the film is confirmed by X‐ray photoelectron spectroscopy results and the Cu 2 SnS 3 shows polycrystalline structure according to Raman spectrum and X‐ray diffraction analysis. The transparent Cu 2 SnS 3 ‐Ga 2 O 3 exhibits the carrier concentration of 5.86 × 10 16 cm −3 , and electrical resistivity of 1.94 Ω·cm. The transparent POS is applied to green quantum light‐emitting diodes (QLEDs) as a hole injection layer (HIL) because of its high work function. The QLED exhibits the maximum current efficiency of 51.72 cd A −1 , power efficiency of 31.97 lm W −1 , and external quantum efficiency (EQE) of 14.93%, which are much higher than the QLED using polyethylene dioxythophene:poly(styrenesulfonate) HIL exhibiting current efficiency of 42.66 cd A −1 , power efficiency of 20.33 lm W −1 , and EQE of 12.36%. The Cu 2 SnS 3 ‐Ga 2 O 3 developed in this work can be widely used as a transparent and conductive p‐type oxide for thin‐film devices.