A photovoltaic device includes a substrate, a semiconductor stack and a transparent tunnel junction. The semiconductor stack includes an n-type layer selected from a first transparent conductive oxide layer, or a window layer, or both; and a p-type absorber layer disposed on the n-type layer, wherein the absorber layer consists essentially of CdSexTe(1-x), wherein x is from 1 to about 40 at. %. The transparent tunnel junction comprises a transparent interface layer of Cd.sub.yZn.sub.(1-y)Te doped to be p+type, and a transparent contact layer doped to be n+type, and the interface layer is disposed between the p-type absorber layer and the transparent contact layer. In bifacial embodiments, the tunnel junction forms a transparent back contact and electrode; and in multi-junction embodiments, the tunnel junction forms a diode-like connector between top and bottom cells. The transparent contact layer may comprise tin oxide or zinc oxide doped with aluminum, fluorine or indium. The photovoltaic device may also include an electron reflector layer and/or an optical reflector layer.

A photovoltaic device includes a substrate, a semiconductor stack and a transparent tunnel junction. The semiconductor stack includes an n-type layer selected from a first transparent conductive oxide layer, or a window layer, or both; and a p-type absorber layer disposed on the n-type layer, wherein the absorber layer consists essentially of CdSexTe(1-x), wherein x is from 1 to about 40 at. %. The transparent tunnel junction comprises a transparent interface layer of Cd.sub.yZn.sub.(1-y)Te doped to be p+type, and a transparent contact layer doped to be n+type, and the interface layer is disposed between the p-type absorber layer and the transparent contact layer. In bifacial embodiments, the tunnel junction forms a transparent back contact and electrode; and in multi-junction embodiments, the tunnel junction forms a diode-like connector between top and bottom cells. The transparent contact layer may comprise tin oxide or zinc oxide doped with aluminum, fluorine or indium. The photovoltaic device may also include an electron reflector layer and/or an optical reflector layer.

A photovoltaic cell can include a dopant in contact with a semiconductor layer.

A photovoltaic cell can include a dopant in contact with a semiconductor layer.

Devices converting light to electricity (such as solar cells or photodetectors) including a heavily-doped p-type a-SiC.sub.y:H and an i-Mg.sub.xCd.sub.1-xTe/n-CdTe/NMg.sub.0.24Cd.sub.0.76Te double heterostructure (DH), with power conversion efficiency of as high as 17%, V.sub.oc as high as 1.096 V, and all operational characteristics being substantially better than those of monocrystalline solar cells known to-date. The a-SiC.sub.y:H layer is configured to enable high built-in potential while, at the same time, allowing the doped absorber to maintain a very long carry lifetime. In comparison, similar undoped CdTe/Mg.sub.xCd.sub.1-xTe DH designs reveal a long carrier lifetime of 3.6 s and an interface recommendation velocity of 1.2 cm/s, which are lower than the record values reported for GaAs/Al.sub.0.5Ga.sub.0.5As (18 cm/s) and GaAs/Ga.sub.0.5In.sub.0.5P (1.5 cm/s) DHs.

Devices converting light to electricity (such as solar cells or photodetectors) including a heavily-doped p-type a-SiC.sub.y:H and an i-Mg.sub.xCd.sub.1-xTe/n-CdTe/NMg.sub.0.24Cd.sub.0.76Te double heterostructure (DH), with power conversion efficiency of as high as 17%, V.sub.oc as high as 1.096 V, and all operational characteristics being substantially better than those of monocrystalline solar cells known to-date. The a-SiC.sub.y:H layer is configured to enable high built-in potential while, at the same time, allowing the doped absorber to maintain a very long carry lifetime. In comparison, similar undoped CdTe/Mg.sub.xCd.sub.1-xTe DH designs reveal a long carrier lifetime of 3.6 s and an interface recommendation velocity of 1.2 cm/s, which are lower than the record values reported for GaAs/Al.sub.0.5Ga.sub.0.5As (18 cm/s) and GaAs/Ga.sub.0.5In.sub.0.5P (1.5 cm/s) DHs.

A photovoltaic device is presented. The photovoltaic device includes a layer stack; and an absorber layer is disposed on the layer stack. The absorber layer comprises selenium, wherein an atomic concentration of selenium varies across a thickness of the absorber layer. The photovoltaic device is substantially free of a cadmium sulfide layer.

A photovoltaic device is presented. The photovoltaic device includes a layer stack; and an absorber layer is disposed on the layer stack. The absorber layer comprises selenium, wherein an atomic concentration of selenium varies across a thickness of the absorber layer. The photovoltaic device is substantially free of a cadmium sulfide layer.

Disclosed are methods for the surface cleaning and passivation of PV absorbers, such as CdTe substrates usable in solar cells, and devices made by such methods. In some embodiments, the method involves an anode layer ion source (ALIS) plasma discharge process to clean and oxidize a CdTe surface to produce a thin oxide layer between the CdTe layer and subsequent back contact layer(s).

Disclosed are methods for the surface cleaning and passivation of PV absorbers, such as CdTe substrates usable in solar cells, and devices made by such methods. In some embodiments, the method involves an anode layer ion source (ALIS) plasma discharge process to clean and oxidize a CdTe surface to produce a thin oxide layer between the CdTe layer and subsequent back contact layer(s).