ELECTRON-SPIN-RESONANCE ON A 2-DIMENSIONAL ELECTRON-GAS

Electron-spin-resonance (ESR) data obtained from modulation-doped Si/S i1-yCy heterostructures are reported. The observed signals show that t he small number of electron spins in these two-dimensional structures is still sufficient to detect ESR directly, and we have strong indicat ions that the prominent line in the spectra is due to conduction elect rons confined in the Si1-yCy layers, forming a two-dimensional electro n gas. We compare our results to the case of confined electrons in III -V heterostructures and quantum wells, where only indirectly detected ESR experiments have been reported so far.