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Photoluminescence Dynamics in Various ZnO Samples Graduate Student: John Wilkinson and Gang Xiong ZnO is a promising candidate for blue and UV LEDs and lasers. It holds several advantages over GaN in material properties. However, it is several years behind GaN in device quality samples. A lack of native p-type ZnO also hinders efforts for an electroluminescent device. In our lab, we investigate and compare the PL dynamics of ZnO samples in various forms using a picosecond streak camera. These include pure and Ga-doped powders, bulk single crystals, poly- and nano-crystalline thin films and nano-crystalline powders. While most of the samples are from external sources, graduate student Gang Xiong is using a sputtering chamber for making ZnO thin films. The samples are excited by either the third or fourth harmonic of a Q-switched Nd:YAG laser (355 or 266 nm, 7 ns) or the third harmonic of the amplified Ti:Sapphire laser (273 nm, 300 fs). Using a closed cycle He refrigerator, we can measure the temperature dependence of the PL from room temperature to 15 K.
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