Magnetic Field Studies of Resonant and Non-resonant Tunnelling in n-(AlGa)As/GaAs Double Barrier Structures
The electrical properties of a series of double barrier tunnelling devices with well widths between 5 and 60 nm are investigated. It is shown that the bistability effect in the current-voltage characteristics of a typical resonant tunnelling device can be removed by connecting a suitable capacitance or resistance to the device. These measurements cast serious doubt on the recent interpretation of the bistability as an intrinsic space-charge effect. In the stabilized section of the I(V) curve, at voltages above the main resonant peak, the magnetoquantum oscillations observed with B‖J are used to investigate tunnelling assisted by LO phonon emission and by elastic scattering processes. The resonant tunnelling device with well width 60 nm exhibits sixteen regions of negative differential conductivity. The effect of a transverse magnetic field J⊥B on the resonances in the I(V) characteristics is investigated. At sufficiently high magnetic field, a transition from tunnelling into hybrid magneto-electric quantised states to tunnelling into magnetically quantised cycloidal skipping states is observed.
Unable to display preview. Download preview PDF.
- 3.See also C. A. Payling, E. Alves, L. Eaves, T. J. Foster, M. Henini, O. H. Hughes, P. E. Simmonds, J. C. Portal, G. Hill and M. A. Pate, Proc. 3rd Int. Conf. on Modulated Semiconductor Structures, Montpellier, France. J. Physique C5, 289 (1987).Google Scholar
- 4.G. A. Toombs, E. S. Alves, L. Eaves, T. J. Foster,. Henini, O. H. Hughes, M. L. Leadbeater, C. A. Payling, F. W. Sheard, P. A. Claxton, G. Hill, M. A. Pate and J. C. Portal, 14th Int. Symposium on Gallium Arsenide and Related Compounds, Crete, 1987. To be published by Institute of Physics.Google Scholar
- 6.F. W. Sheard and G. A. Toombs, Appl. Phys. Lett., to be published, April 1988.Google Scholar