Electrical and photoelectric properties of transparent Li-doped ZnO/ZnO homojunctions by pulsed laser deposition

(002)-Preferred orientation ZnO and Li-doped ZnO thin films on glass substrates and Li-doped ZnO/ZnO bilayers on fluorine-doped SnO₂ glass substrates are grown by pulsed laser deposition technique. These films are characterized by X-ray diffraction, UV–visible transmission spectroscopy, surface photovoltage spectroscopy, and electric measurements. The optical transmittance of Li-doped ZnO/ZnO bilayers is about 86%. The bilayer grown on FTO glass substrates exhibits a typical rectifying characteristic of p–n heterojunctions. In addition, the photovoltaic response of ZnO is blue-shifted from 380 to 363 nm and greatly enhanced resulting from the formation of p–n homojunctions based on ZnO. - Highlights: • Li-doped ZnO/ZnO p–n bilayers are grown on F-doped SnO₂ by pulsed laser deposition. • The bilayers exhibit a typical rectifying characteristic of p–n heterojunctions. • Formation of homojunctions greatly enhanced the ZnO photovoltaic response