In {HEAD ~ a preferred embodiment}, {TAIL ~ the p type zinc oxide film} contains arsenic and is grown on a gallium arsenide substrate 
In { HEAD ~ a preferred embodiment } , { TAIL ~ the p type zinc oxide film } contains arsenic and is grown on a gallium arsenide substrate
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH