Doping Induced Defects of Cd1−xZnxTe Grown from Te Solution

Abstract

A comparison is made for undoped and lightly indium‐doped Cd1‐xZnxTe grown from Te solution by using photoluminescence and admittance spectroscopy to study the doping behavior in Cd1‐xZnxTe. Two acceptor traps are found to be induced by In doping: one is located at about 0.15 eV above the valence band, which is the well‐known A‐center, and the other is located at Ev + 0.27 eV with the capture cross section of 8.4 × 10−14 cm2.

Cathodoluminescence and photoinduced current spectroscopy studies of defects inCd0.8Zn0.2Castaldini1, Cavallini2, Fraboni3 et al. 1996Phys. Rev. B403170View full textAdd to dashboardCite

“…9 The fact that level A follows the valenceband behavior confirms its attribution to a Cd sublattice defect. 6 Level B: The level determined by PICTS measurements to be located at 0.25 eV could be related to the level at 0.31 eV found in PICTS investigations of Cd 0.9 Zn 0.1 Te and attributed to Zn, 10 or to the one at 0.27 eV found in Cd 1Ϫx Zn x Te:In and again assigned to a Zn-related defect. 6 The Zn attribution is supported by the absence of such a level in PICTS analyses of CdTe doped and undoped samples.…”

“…5,6 Moreover, the band gap varies with Zn concentration from 1.45 eV in CdTe to 2.3 eV in ZnTe. For the ternary compound Cd 0.8 Zn 0.2 Te here investigated, the band gap is 1.65 eV at room temperature.…”

Identification of deep trap levels from thermally stimulated current spectra of semi-insulating CdZnTe detector material

“…Trap T 5 ͑0.276 eV, 2.4ϫ 10 −17 cm 2 ͒, according to E a , corresponds to the 0.27 eV level of Suzuki et al 32 and of Larsen et al 33 It is also close to level E 2 ͑0.26 eV͒ observed in the TEES spectra obtained by Zerrai et al 7 Trap T 6 ͑0.298 eV, 9.1ϫ 10 −18 cm 2 ͒ with a peak at 155 K is at the same position as the peak of level X found by Cavallini et al 25 The concentration of this level increased after low-energy neutron irradiation of their CdZnTe detectors and decreased after one year rest period.…”

Comparison of electrical and luminescence data for the A center in CdTe

“…In fact, the 1.4 eV band has been reported in the literature to be present in most II-VI compounds, independently of doping and growth method. 6,7,[12][13][14][15][16] This implies that there might be other native defects/complexes, extended defects or residual impurities which either emit in the spectral range 1.3-1.5 eV or form complexes with the available V Cd . Therefore, the 1.4 eV band might not be necessarily related to an actual A center.…”

“…Therefore, the 1.4 eV band might not be necessarily related to an actual A center. 6,8,13,14,17 We have studied the various components of the 1.4 eV band in order to understand which ones could be reliably attributed to the A center. The techniques we have utilized are cathodoluminescence ͑CL͒ and junction spectroscopy, such as deep level transient spectroscopy ͑DLTS͒, 18 PICTS, 19 and photo-DLTS ͑P-DLTS͒.…”