Photovoltaic device with a zinc magnesium oxide window layer
View Patent ↗Methods and devices are described for a photovoltaic device and substrate structure. In one embodiment, a photovoltaic device includes a substrate structure and a CdTe absorber layer, the substrate structure including a Zn 1-x Mg x O window layer and a low conductivity buffer layer. Another embodiment is directed to a process for manufacturing a photovoltaic device including forming a Zn 1-x Mg x O window layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process and vapor transport deposition process. The process including forming a CdTe absorber layer above the Zn 1-x Mg x O window layer.
1. A photovoltaic device comprising:
a glass substrate;
a barrier layer over the substrate;
a transparent conductive oxide layer over the barrier layer;
a buffer layer over the transparent conductive oxide layer;
a first semiconductor window layer over the buffer layer, the first semiconductor window layer comprising Zn 1-x Mg x O, wherein 0<x<1;
a second semiconductor window layer comprising cadmium sulfide over the first semiconductor window layer; and
a cadmium telluride semiconductor absorber layer over the second semiconductor window layer;
wherein the conduction band offset of the first semiconductor window layer with respect to the cadmium telluride semiconductor absorber layer is in the range of 0 to +0.4 eV.
2. The photovoltaic device of claim 1 , wherein the first semiconductor window layer is on the buffer layer.
3. The photovoltaic device of claim 1 , wherein the thickness of the first semiconductor window layer ranges from about 2 nm to about 2000 nm.
4. The photovoltaic device of claim 2 , wherein the conductivity of the first semiconductor window layer is within a range of about 1 mOhm per cm to about 10 Ohm per cm.
5. The photovoltaic device of claim 2 , wherein the first semiconductor window layer is doped with Al, Mn, Nb, N, F or by introducing oxygen vacancies.
6. The photovoltaic device of claim 2 , wherein:
the barrier layer is between the glass substrate and the transparent conductive oxide layer.
7. The photovoltaic device of claim 1 , wherein the first semiconductor window layer is doped with Al, Mn, Nb, N, F or by introducing oxygen vacancies.
8. The photovoltaic device of claim 1 , wherein the first semiconductor window layer has a dopant concentration of between about 1×10 14 cm −3 and about 1×10 19 cm −3 .
9. The photovoltaic device of claim 8 , wherein the first semiconductor window layer has a dopant concentration of between about 1×10 17 cm −3 and about 1×10 18 cm −3 .