Deep donors inCd1−xZn

Tineke Thio¹,

J. W. Bennett²,

P. Becla

³

Abstract

Measurements of the persistent photoconductivity ͑PPC͒ and Hall effect in Cl-doped Cd 1Ϫx Zn x Te indicate that the Cl donors form several distinct deep DX states, consistent with recent calculations. For xϭ0.20 only one DX state is evident, with a deep binding energy E d ϭ0.22 eV; the PPC has a single annealing transition at T a ϭ130 K. For xϭ0.28 the PPC has two distinct transitions, at T b ϭ100 K and T a ϭ190 K. We propose a model in which the presence of a second metastable state DXЈ boosts T a significantly. For xϭ0.28 the DXЈ lies 0.23 eV below the conduction band, whereas the deepest binding energy is E d ϭ0.40 eV. The rapid increase of E d with x explains the difficulty of obtaining n-type ZnTe using Cl dopants. Nevertheless, these materials are interesting because DX centers with large E d and high T a are potentially useful in optoelectronic applications.

What causes high resistivity in CdTe

“…For both donors, the shallow-donor and the DX-center energy lines intersect at a point above the CBM (see figures 6 and 7). Thus, the Cl and In DX centers are not stable unless the band gap can be increased by applying pressure or by alloying with Zn, as also found experimentally [59][60][61]. Our results show that the shallow donors are compensated by V Cd and A centers, not by DX centers.…”

DXCenters in Ionic SemiconductorCdF2:Ga

“…To describe the temperature dependence of the shallowcenter thermal decay we employed a model similar to that which Thio et al [16] used for analysis of deep donors in Cd 12x Zn x Te:Cl (Fig. 4).…”

Probing the magnetic ground state of theDX−center inCd1−xMnxGiblin1, Terry2, Read3 et al. 2006Phys. Rev. BSelf Cite2010View full textAdd to dashboardCite

“…Resistivity measurements indicate that the shallow donor binding energy for I1 is ϳ220 K and ϳ150 K for A1. We observe only one quenching temperature at 100 K, however, other investigations into Cd 1−x Mn x Te: In 22 and Cd 1−x Zn x Te: Cl 24 have recorded another higher quenching temperature proving the existence of more than one possible deep center, which have been theoretically predicted. 23 It is believed that heavy doping levels of the crystals could also contribute to multiple DX states.…”