Hot electron effects and phonon emission from a two-dimensional electron gas (2 DEG)

An investigation has been made of the phonon emission from a heated 2DEG in a (100) Si MOSFET for power inputs down to 10 mu W mm-2. For sheet densities 0.7<or approximately=ns<or approximately=4.9*1016 m-2 the steady increase in phonon intensity I opposite the 2DEG as ns falls at constant power input is attributable to in-plane momentum conservation, q11<or approximately=2kF. I falls as ns is further reduced and the authors attribute this to an increase in the proportion of LA phonon emission. For ns<or approximately=3*1015 m-2 there is a significant fall in the proportion of energy emitted as phonons suggesting an increase in FIR emission. The rise in I for ns<or approximately=4.9*1016 m-2 is attributed to the occupation of a subband of excitation energy 31 meV.