Structural and electronic properties of CdTe_1-xSe_x films and their application in solar cells

Figures & data

Figure 1. X-ray diffractograms of CdTe_1-xSe_x thin films on glass substrate. The symbols indicate the CdTe reference from [18] (PDF number 01–070–8041).

Figure 2. Splitting of the 311 Bragg reflex of CdTe_1-xSe_x thin films on glass substrate. The reference value for the CdTe peak is from [18].

Figure 3. Lattice constant of CdTe_1-xSe_x thin films on glass substrate. The value for zinc blende CdSe (x = 1) was taken from literature [23].

Figure 4. Tauc plots of CdTe_1-xSe_x thin films on glass substrate with linear fitting to extract the band gap.

Figure 5. Band gap of CdTe_1-xSe_x thin films on glass substrate determined from the Tauc plot. The band gap value for the pure CdSe (x = 1) was taken from literature [25].

Figure 6. Results from resistivity measurements with the transmission line method at 25 °C (a) and from Hall effect measurements at 70 °C (b–d) of CdTe_1-xSe_x thin films on glass substrate with Cu doping variations for x = 0, 0.1, 0.2 and with an additional x = 0.08 sample with lower Cu doping.

Table 1. Performance parameters of CdTe solar cells with and without CdTe_1-xSe_x grading of the absorber towards the CdS window layer, and with varying CdS window layer thicknesses.

Cell	CdSe on top of CdTe	CdS thickness	V OC	J SC (EQE)	FF	Efficiency	Band gap (EQE)
	[nm]	[nm]	[mV]	[mA/cm^2]	[%]	[%]	[eV]
Standard CdTe	0	120	830 ± 1	18.5 ± 0.5	69 ± 4	10.5 ± 0.1	1.49 ± 0.01
CdTe with thin CdS	0	60	691 ± 1	17.3 ± 0.5	52 ± 4	6.2 ± 0.1	1.49 ± 0.01
With CdTe1-xSex	50	60	738 ± 1	22.5 ± 0.7	69 ± 4	11.5 ± 0.1	1.44 ± 0.01
With CdTe1-xSex	60	30	710 ± 1	25.6 ± 0.8	67 ± 4	12.2 ± 0.1	1.43 ± 0.01

Figure 7. JV performance parameters of CdTe solar cells with and without CdTe_1-xSe_x grading of the absorber towards the CdS window layer, and with varying CdS window layer thicknesses.

Figure 8. Current-voltage curves of CdTe solar cells with and without CdTe_1-xSe_x grading of the absorber towards the CdS window layer, and with varying CdS window layer thicknesses.

Figure 9. External quantum efficiency of CdTe solar cells with and without CdTe_1-xSe_x grading of the absorber towards the CdS window layer, and with varying CdS window layer thicknesses.

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