Articles you may be interested inNearresonant vibrational energy transfer in ozone. Doubleresonance measurements and calculations in the temperature range 200-300 K The laser fluorescence method. whereby CO molecules are optically pumped from the vibrational level v =0 to the v = I state by frequency·doubled pulses from a CO 2 laser. has been used to determine vibrational energy transfer rate coefficients for CO. Rates for the V -V exchange processes CO(O)+NZ

A new phenomenon in rf glow discharges has been observed, namely the existence of a strongly time dependent excitation of atomic levels. The observed excitation width of 10 ns (FHWM) is short compared to the 37-ns duration of a half-cycle of the 13.56-MHz applied rf power. This implies a similar time dependence of the density of those electrons responsible for the excitation. Moreover, the excitation propagates through the glow away from the nearer electrode. The nature of this propagation phenomenon is uncertain. These results are deduced from a time resolved study of the λ=288.2 nm emission from neutral excited silicon, Si(4s1,1P0) and λ=656.3 nm emission from H(n=3), generated within the rf silane glow discharge. The radiative lifetimes of these two states are 5.2 and 10 ns, respectively. A study of the Si to H yield ratio, together with some Langmuir probe measurements, indicates that the electrons are themalized in the glow regions.

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The use of electrostatic probe techniques for measurement of the electron temperature kTe and the electron density ne in pure and BF3 doped silane radio frequency (13.56 MHz) discharges is demonstrated to be feasible even though amorphous silicon is being deposited on the probe surfaces. The required conductivity of such deposited silicon surface layers is examined and compared with the measured photoconductivity and thermally induced conductivity of amorphous silicon. An equation is derived for the double probe current–voltage (I–V) curve which includes the first order effect of ac fields and can be used to determine the electron density. During typical depositions of thin films of amorphous silicon from such discharges, values of kTe =2–2.5 eV and ne =(1–1.5)×109 cm−3 were obtained. These values are consistent with those obtained by other workers using microwave and optical techniques. In BF3 doped silane an abrupt step is observed in the Langmuir I–V curves which indicates the presence of a group of fast, anisotropic electrons. In diborane doped silane, probe measurements become unstable and irreproducible. For this reason we investigate a rf probe technique. The advantages and constraints inherent in using this method in our rf discharges are examined and analyzed.

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