Regulation of Te Oxide Layer on Cdznte Film for Adjusting Surface Contact of a Cdznte-Based Device

The control of the interface states between the electric contacts and semiconductor is a key issue to develop high-performance functional devices. In this work, a serial of surface treatments including mechanical polishing (MP) + chemical polishing (CP) + surface passivation (SP) were conducted to improve the surface states of the CZT film. A transparent Ga-doped Zinc oxide (GZO) was used as the electrode to fabricate the metal-semiconductor-metal (MSM) CZT-based device. The combined surface treatments greatly improved the surface contact between the CZT film and the GZO electrodes. By controlling the thickness of the Te oxide layer on the CZT film surface through atmospheric oxidation (AO) and no-atmospheric oxidation (NAO), the thickness of oxide layer on the CZT film surface was adjusted. The X-ray photoelectron spectroscopy (XPS) was used to observe the oxidation sate of the Te oxide layer. The thickness of the Te oxide layer of CZT film surface in atmosphere environment was evaluated as 18~20 nm through the in-situ XPS measurement, while that of the CZT film in insolated atmosphere was 5~7 nm. In contrast, the CZT film-based device under the combination treatments of MP + CP + SP + AO exhibit a surface roughness of ~4 nm, leading to a marked reduction in the leakage current. The present work provides a strategy to control the thickness of Te oxide layer of CZT film surface and fabricate a device with a lower current