Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

154 Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

© 2011 by Taylor & Francis Group, LLC

X-ray diffraction was used to determine the crystallinity of the phosphorus-doped ZnO lms rel-

ative to undoped ZnO lms. Based on the bulk phase diagram for ZnO-P

2

O

5

, the solid solubility of

phosphorus in ZnO should be limited and metastable. Indications that the solid solubility has been

exceeded in the lms would be the appearance of impurity phases or a saturation of dopant-relevant

material properties with increasing doping. The diffraction data shows only ZnO (000ℓ) and sub-

strate peaks. The lms are oriented in a plane as determined by a four-circle x-ray diffraction. Note

that some degradation in x-ray diffract ...