Conduction Mechanisms for Electronic Devices.
Interim rept. 3 May-2 Oct 72,
RCA LABS PRINCETON N J
Pagination or Media Count:
Previously developed techniques of preparing controlled energy band tails in heavily doped, closely compensated GaAs are being exploited to exhibit the electronic transport properties in band tails. These properties closely resemble the corresponding properties of amorphous semiconductors but the control available in the present materials has added greatly to the capabilities necessary for understanding the unclear behavior in amorphous semiconductors. A systematic program of relating several different properties has been started to increase the value of the separate measurements e.g., temperature and electric field dependence of the d.c. conductivity, a.c. conductivity, and photoconductivity. One of the specific results of primary interest was the highly detailed, accurate measurement of the temperature dependence of the d.c. conductivity which displayed the relation Log sigma approximately equal to T to the minus 12 power. Theory indicates that this suggests one-dimensional conduction in the band tails since normal, three-dimensional conduction should give log sigma approximatelyT to the-14 ower. The other major result showed that the low-temperature conductivity has a nearly exponential dependence on electric field strength, extending down to approximately 2 Vcm. This very low-field sensitivity is unexpected and is the basis for increased understanding of the electronic behavior in band tails. Author
- Solid State Physics