The effects of alkali metal diffusion on zinc phosphide thin films

Zinc phosphide (Zn
₃
P
₂
) thin films are grown by close-spaced sublimation. Three substrates were chosen to grow thin films: soda lime glass, mica, and quartz. C-V measurements were performed to determine the majority charge carrier concentration of the 2-5μm Zn
₃
P
₂
thin films. Quartz (no alkali metals) had an average charge carrier density of 1×10
¹⁵
cm
^-3
; whereas mica (some alkali metals) had 3 times the carrier density of quartz. The concentration of charge carriers for soda-lime glass substrates could not be determined due to a bad junction with Magnesium. This is potentially related to the high concentration of sodium in soda-lime glass.