Spectroscopy of Excited Acceptor States in GaP

Abstract

This Letter reports a novel method to observe donor and acceptor excited states, and its application to C, Mg, and Zn acceptors in GaP. We evaluate valence-band parameters and ionization energies independently of other measurements, and resolve many uncertainties in the basic parameters characterizing GaP. Detailed information about the donor-acceptor (D-A) interaction is obtained more directly than with any other method.We measure photoluminescence excitation spectra of D-A pair transition. The ground state of a D-A pair with separation R decays with lumi-. 12 No distinction is made here between bona-fide surface states and strong surface resonances, and in discussing the character of the surface states we are concerned only with the main d character of the wave functions.13 Symmetry gaps are gaps along high-symmetry lines in the PBS in which bulk states of a given symmetry are forbidden but where states of other symmetry may exist. (1) where £ D and E A are the donor and acceptor binding energies, E g is the band gap, and J is the interaction energy of a neutral-donor-neutral-acceptor pair. Luminescence from D-A pairs of a selected R is observed by choosing an appropriate tiw L , and the emission intensity is recorded as a function of excitation energy fru> x . A dye laser with linewidth 0.3 meV is used as excitation source.A peak in the excitation spectrum corresponds Luminescence excitation spectroscop}' of donor-acceptor pair recombination in GaP is reported. We observe s and/) excited states of C, Mg, and Zn acceptors, and deduce acceptor binding energies and Luttinger valence-band parameters (y 1 = 4.04, y 2 = 0.53, and y 3 = 1.26). Directly obtained information on the interaction between donors and acceptors characterizes the acceptor state and confirms observation of the lS 1/2 level. 1292

Band parameters for III–V compound semiconductors and their alloys

“…Street and Senske also determined Luttinger parameters from acceptor binding energies. 199 Those parameters as corrected in Landolt-Bornstein 1 are in reasonably good agreement with cyclotron resonance results, and may be considered the most reliable: ␥ 1 ϭ4.05, ␥ 2 ϭ0.49, and ␥ 3 ϭ1.25. A split-off hole mass of 0.23-0.24m 0 was calculated by Lawaetz 106 and by Krijn.…”

Selective magneto‐luminescence spectroscopy of donoacceptor pairs in n‐GaAs

“…7, 8). The energy shift corresponding to the 1s-2p -1 transition decreases, which could be understood as a result of a screening of the acceptor by the donor potential [5,6]. What is more interesting is that the spin flip transitions are also modified, showing clear splitting for excitation energies larger than 1.500 eV (Figs.…”

“…In this case, the ES experiments can be performed on several lines corresponding to specific donor-acceptor separations. Such spectroscopy, when, for example, applied to GaP, allows the identification of several excited states of shallow acceptors, and provides information about valence-band parameters [5,7].…”

“…In order to investigate pairs at large separations one has to use low excitation energy, whereas to excite close pairs a higher excitation energy should be used. For weakly interacting pairs (namely those with large separation) the energy shift between exciting and emitted photons should reproduce the intradonor and/or intra-acceptor transitions which are typical for isolated centers, whereas for the close pairs, the influence of the axial pair potential on the individual donor and acceptor states can be studied [5,7]. A natural extension of SPL is magneto-spectroscopy, which opens new possibilities in the studies of the excitation of a donor-acceptor pair system.…”

Excitation and recombination of donor–acceptor pairs in ZnTe

“…The photoluminescence excitation spectroscopy [2] will be the most powerful method to study the excited states of localized centres whose emission spectra show inhomogeneous broadening. The broad d-a pair band is an example.…”