Polaron, Zeeman, and Diamagnetic Effect in the Recombination Spectra of Donor Bound Excitons in Cadmium Telluride

Abstract

Cadmium telluride has long been recognised a s an almost ideal material in which to study polaron coupling phenomena in the magneto-optical spectra of hydro- We report measurements in the near infra-red ( -1 . 6 eV) on the high-field magneto-optical properties of the two-electron lines of the donor photoluminescence spectrum. These a r e due to recombination of neutral donor bound.excitons which leave the donor in excited states ( 2 ) , l ) those same states which were subjects of earlier studies by f a r infra-red absorption (1), (3). We have been ahle to approach the pinning energy corresponding to the resonance of the 1s-2p transition with the LO phonon more closely than hitherto. Strong emission bands due to phonon assisted free exciton recombination obscure part of the region of interest, a feature which could be avoided by direct excitation of donor bound excitons by a tunable laser. +Our measurements were taken photographically at fields up to 125 kG, frequently at intervals of 1 kG o r less. The positions of the luminescence lines are shown in Fig. l a . The intensities of many of the lines, particularly those associated with the phonon replication, a r e P 0 . 1 % of the intensity of the principal donor bound exciton recombination line (not shown). The latter is accompanied by a number of lines due to excited states of the bound exciton which add appreciable complication t o the two-electron spectrum (2). 1) Reference (2) describes the Zeeman effect in the two-electron lines at magnetic fields below 50 kG.

Novel Approach to Preparation of InP Layers for Radiation Detectors

“…The binding energy of the dominant acceptor determined from the slope of the straight line and corrected by the T 3/2 term is equal to 0.22 eV. This value is close to the binding energy of Ge acceptor 210 ± 20 meV [7] and also to the binding energy of Mn acceptor 230 meV [8]. Both these elements are possible candidates for being the dominant acceptors and they could be hardly distinguished on the basis of temperature dependent Hall measurement alone.…”