Fig. 1
Four CdTe ingots used in this study: un-doped, doped with Cl at concentrations of 4.97 × 1019 cm−3, 9.94 × 1019 cm−3 and 1.99 × 1020 cm−3.
Fig. 2
XRD measurement results of 12 samples from four ingots with different Cl doping concentrations, chosen from top, middle and bottom sections, respectively.
Fig. 3
Typical IR microscope images of Te inclusions for three samples with Cl doping concentrations of 4.97 × 1019 cm−3, 9.94 × 1019 cm−3 and 1.99 × 1020 cm−3. The solid lines appearing on the surfaces might be due to the scratches induced by incompletely optimized polishing processes.
Fig. 4
Histogram of Te inclusions size distribution for three Cl-doped CdTe samples.
Fig. 5
(a) Dielectric response curves of undoped and doped (1.99 × 1020 cm−3) CdTe sample, (b) α2vs. photon energy (hν, in eV) with extrapolation of the linear part of the curves to α = 0, (c) second derivative plots of ε1 shown in Fig. 5a.
Table 1
Average resistivities of the CdTe samples with different Cl doping concentrations and different positions within the ingots. Mean values for each row/column were also calculated and presented in the Table.
| Top [Ω·cm] | Middle [Ω·cm] | Bottom [Ω·cm] | Mean [Ω·cm] | |
|---|---|---|---|---|
| Undoped | 5.20 × 104 | 1.33 × 104 | 1.60 × 104 | 2.71 × 104 |
| Cl doped, 4.97 × 1019cm−3 | 3.56 × 106 | 5.70 × 109 | 2.07 × 109 | 2.59 × 109 |
| Cl doped, 9.94 × 1019cm−3 | 1.06 × 109 | 8.03 × 109 | 3.35 × 109 | 4.15 × 109 |
| Cl doped, 1.99 × 1020cm−3 | 2.19 × 109 | 1.44 × 1010 | 2.11 × 109 | 6.22 × 109 |
| Mean [Ω·cm] | 8.15 × 108 | 7.02 × 109 | 1.88 × 109 |
Fig. 6
(a) Average resistivities of CdTe samples as a function of Cl doping concentrations. Solid fitting line was provided as a guide for the eyes; (b) average resistivities of CdTe samples from different locations within the ingots (Fig. 1). Solid fitting line was provided as a guide for the eyes.