DX CENTER IN SI-DOPED ALXGA1-XAS - CHARGE STATE AND CAPTURE MECHANISM

We discuss the capture mechanism into the D- ground state of the so-called DX centre in AlxGa1-xAs. Using experimental data for the thermally activated capture of electrons on DX centres in Si-doped AlxGa1-xAs samples in the region of x congruent-to 0.3 under pressure, we show that, if the emission from the intermediate neutral state of DX centres is activated, then an upper limit can be set for the value of the emission activation energy in Si-doped Al0.33Ga0.67As: DELTA-E(em)0 < 150 meV. This value is much less than the activation energy seen in DLTS, which is the activation energy for the emission from the negative ground state DELTA-E(em)-. In emission experiments such as DLTS performed in Si-doped AlxGa1-xAs, both electrons are emitted practically at the same time.