Measurements were carried out on salmon DNA-based films, including as-received DNA (molecular weight,
MW>2000 kDa) without and with hexacetyltrimethl-ammonium chloride (CTMA) surfactant, and sonicated DNA
of MW~200 kDa with CTMA. The test specimens were spin-coated or drop-cast films on ITO-coated quartz
slides with a gold charge-collecting electrode. To protect the films from atmospheric influences, the TOF devices
were coated with a 200-400 nm polyurethane passivation layer. A quadrupled 20 ns, pulsed Nd:YAG laser with
output at 266 nm was used for charge injection. The room temperature photoconductive transients were dispersive
to varying degrees with hole mobilities in DNA materials films ranging between 2E-5 to 6E-3 cm2/Vs for fields
ranging from 8 to 58 kV/cm. Only hole response was observed in DNA. The dispersive data were analyzed using
a simple, quasi-empirical equation for the photocurrent transient data.
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