D'yakonov-Shur instability in a ballistic field-effect transistor with a spatially nonuniform channel

The instability of a two-dimensional electronic liquid in the channel of a ballistic field-effect transistor is analyzed by investigating the energy balance. A criterion of instability is found for arbitrary boundary conditions. Using energy-balance analysis we propose a device with a high instability growth rate. The transistor possesses a spatially nonuniform channel and is analogous to a divergent channel in classical hydrodynamics. Our computed growth rate and threshold of the instability for this device agree with the computational data. (C) 1999 American Institute of Physics. [S1063-7826(99)02005-0].