Spectroscopic evidence for the interaction between shallow hydrogenic donors in GaAs, InP and CdTe

Impurity cluster effects in high‐ and low‐doping semiconductor materials

“…we observe that the transitions are roughly related to E (1 s –2 p ± ) > 0.6 $ E_{\rm D} ^*$ . The calculated MCSCF peak energy E(Pε 2 ) for the transition derived from the ionization energy of both oxygen in GaN and silicon in GaAs are in excellent agreement with the experimental finding of ∼19.2 meV and ∼3.0 meV13, 2. We predict a prominent peak of ∼27 meV for phosphorous in Si in agreement with Ref.…”

“…This ionization energy from the H 3 transition corresponds in our model to the energy required to promote one electron from the three- are from Ref. [2] for GaAs and Ref. [17] for GaN. donor molecule to the bottom of the CB.…”

“…Work to date has concentrated on the search for optical transitions of donor impurities [1,2,[9][10][11][12][13] once a peak appeared in the experimental investigations on the low-energy side of the 1s to 2p transition in Si, GaAs, GaN n-type doped semiconductors. The first attempt to explain such lowenergy peak as arising from donor-cluster transitions were carried out by the Heitler-London approximation [14] and by Golka and Piela [15], who used a Hartree-Fock method [5].…”

“…As the impurity concentration increases, donor clusters rapidly become important. As the clusters get more dense, the absorption edge drops as one would expect that the donor clusters will absorb at low energies, below the ionization and transition levels of the isolated impurities2–5. Above a certain critical doping concentration N c , the donors (in n ‐type materials) spontaneously become ionized due to strong impurity–impurity interaction.…”