Pulsed bias

Apparatus for parallel-in to serial-out conversion is shown in GB-A-2007909. According to this invention a stationary image is focussed on the detector and a standing distribution of ambipolar carriers is allowed to accumulate. After an accumulation period a pulsed bias current is applied to sweep the carriers to the read-out region. 

Polymerization is induced with the STM tip. STM images of the monolayer of NCDA before and just after applying a positive pulsed bias voltage of 4Y are shown in Fig. 19. In Fig. 19a, a number of parallel lines corresponding to the diacetylene portions of NCDA molecules are observed. 

Fig. 21. Dependence of DFM-AFM lithography on the pulse bias voltage and the application time of pulse bias (a) illustration of the pulse bias voltage and application time of pulse bias used, (b) topographic image and (c) surface potential image.

Combination of a pulsed bias and noncontact AFM has been found to improve the control of the writing process [78]. This method reduces the tip-substrate interaction time and thus improves the reliability and lithographic resolution. The frequency of oscillation and the field pulsing frequencies need to be adjusted to create a definite phase relation between the two and it was found that the minimum line width is obtained when the applied field is on during the time the cantilever tip is furthest from the substrate. The process also needs adjustment of the duty cycle. 

High protection of atoms in the TOT from the influence of the environment favors coherence of their electrical response (nutations and echoes) to pulsed bias. 

Fig. 5.3.8 Notching in narrow trenches (left) straight sidewalls down to the bottom obtained with pulsed bias (right)...

A remark appears indicated about the measurement of the power of a picosecond diode laser. The sensor in power meters for the 10 pW to 10 mW range is usually a silicon photodiode. The photodiode is connected to a transimpedance amplifier that holds the diode voltage at zero and delivers an output voltage proportional to the diode current. Of course, the amplifier is far too slow to reaet to the fast diode laser pulses. Consequently, the pulses bias the diode in a forward direction. The result is a logarithmic dependence of the voltage on the input power. At a 50 MHz repetition rate, the linearity error usually becomes notieeable above 1 mW average power and can easily reach 100% at 5 mW. The problem ean be avoided by operating the photodiode with a reverse bias. It is normally not known whether a particular power meter uses a biased or an unbiased photodiode. 

A positive inter-pulse bias voltage between 0.4 and 0.8 V versus Ag AgCl can increase the charge injection capacity of iridium oxide up to as high as three... 

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