Lauren Cantley
Part of the family of group II-IV nitride semiconductors
Closely related to group III nitrides◦ Band gap◦ Crystal lattice structure
To date there has been no reported growth of ZnSnN2
ZnSnN2 predicted to be analogous to InN
Because of their similar properties, group II-IV nitrides are predicted to have similar applications as group III nitrides
Also expected to be superior to group III nitrides in certain instances◦ Predicted to have smaller range of lattice
constants for same band gap range◦ Could resolve issues associated with clustering
To synthesize ZnSnN2 – completing the first ever reported growth!
To determine the optimal conditions under which the growth of ZnSnN2 can occur
High Vacuum Plasma System◦ RF plasma source◦ Vacuum pumps and
chamber◦ Experimental
package◦ Crucible and heater◦ Various gauges to
monitor growth conditions
o Experimental packageo Crucible and heater
Zinc is volatile However, evaporation of zinc can be
suppressed within a Zn-Sn liquid alloy rich in tin
Also can suppress evaporation by working at higher pressures
Metals must melt and form a liquid alloy at a temperature lower than the growth temperature
No conflicts of interest between suppressing the vapor pressure of zinc and melting the alloy together
Zinc oxidizes readily under normal atmospheric conditions
Oxide layer melts at temperatures higher than the range of the heater
If Oxide layer present, Zinc won’t coalesce Remove oxide layer by flowing hydrogen
plasma into the system
Pressure: 150 mTorr Temperature: 400 C or 500 C Composition of Zn-Sn alloy melt:
10 wt% Zn90 wt% Sn
Growth period: 4.5 hours Plasma:
◦ 60 watts forward power◦ 10 sccm of nitrogen◦ 5 sccm of hydrogen
Growth temperature: 400 C Nitrogen plasma off during
coolingMagnification: 20x
XEDS
X-ray energy dispersive spectroscopy
X-Ray Mapping
N
Zn
Sn
300μ
m
300μm
Growth temperature: 400 C
Nitrogen plasma on during cooling
Magnification: 50x
Magnification: 10x
Growth temperature: 500 C Nitrogen plasma on during cooling until sample
reached 400 C
No film was found on the surface of the sample Sample was found to have a 9.1 wt% loss in mass
after growth period. Initial composition of the sample was 9.1 wt% zinc
Leads us to believe all the zinc evaporated at the higher temperature
Material grown on the surface of sample 1 most likely to be ZnSnN2
Unable to confirm the growth of ZnSnN2
Unable to fully explore phase space in which ZnSnN2 is presumed to be stable
However, these initial growths are a good starting point for further research