P6.2 - Observation of Hopping Multi-Domains
- SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
- Proceedings SENSOR 2011
- P6 - Technology, Materials
- Z. Adamia - Tbilisi State University (Georgia)
- 797 - 799
The investigation deals with the hopping transport region. The hopping transport can occur in semiconductors at a temperature decrease. In this case a charge transfer takes place in impurity centers located randomly and energy scattered. In the present work experimental data confirming the formation of several electric domains moving simultaneously in the sample bulk with the velocity of c=2.5mm/sec in the region of temperature saturation of hopping conductance are presented. The phenomenon was observed in the samples of weakly doped p - Si with low degree of compensation. The acceptor concentration was 7·1016cm-3 and the compensation was of the order of 10-4. A multidomain was formed within the temperature range of 7-14K. The maximum electric field strength was observed in the temperature region of 10K. Here, supply voltage pulses above the critical value and with the rise time less than Maxwel time of bulk charge formation were applied to the sample. During the whole period of a voltage pulse a drop of the current passing through the sample was observed which is due to the negative differenttial resistance. At this time the current drop was stronger than that during appearance of a single domain. The result can be explained on the basis of the Nguyen and Shklovskii theory predicting the negative differential conduction in the hopping conduction region. A method allowing electric investigations of high - ohmic samples is described.