Observation of low frequency oscillations in GaAs samples grown by molecular beam epitaxy at low temperatures

We have observed Low Frequency Oscillations (LFO) in a GaAs sample grown by molecular beam epitaxy (MBE) at 300 degrees C as a function of applied ele ctric field, temperature and illumination intensity. Time series of the osc illations for different values of the applied electric field at room temper ature were obtained. We have also obtained the jxE characteristics as a fun ction of temperature and light intensity. We were able to control the LFO u sing three experimental parameters, the electrical field, which controls th e oscillation frequency, and the temperature and illumination intensity, wh ich control the carrier density and field-enhanced trapping. We were able t o identify the LFO dependence on the carrier density and on the field-enhan ced trapping.