Growth of Cd1-xZnxTe thin films with high Zn content by close-spaced sublimation

•The CdZnTe films with Zn content as high as 0.42 are achieved.•A high sticking coefficient ratio of Zn to Cd is one of two key factors to obtain CdZnTe films with a high Zn content.•A high Zn vapor pressure under low growth pressure is another key factor to obtain CdZnTe films with a high Zn content.

The Cd1-xZnxTe films with a high x value of about 0.42 were achieved by close-spaced sublimation (CSS) method using a pre-alloyed CdZnTe source on the basis of two critical growth factors. A relatively high growth temperature is one of two key factors to achieve high Zn content in CdZnTe films. The x value of Cd1-xZnxTe varies from 0.10 to 0.42 as the substrate temperature changes from 100 to 500 °C under the pressure of 10 Pa. Moreover, it can be inferred that the sticking coefficient ratio of Zn to Cd is about 2.5–4 times at 500 °C than that at 400 °C. The other factor, more importantly, is the growth pressure, which should be below 10 Pa, while a high pressure of above 1000 Pa generally adopted in the Cd1-xZnxTe films using the CSS method always leads to Cd1-xZnxTe films with a low x value. The sudden increase of Zn vapor pressure under a growth pressure lower than 10 Pa is responsible for a high Zn content in the Cd1-xZnxTe films.