According to the embodiments provided herein, a method for scribing a layer stack of a photovoltaic device can include directing a laser scribing waveform to a film side of a layer stack. The laser scribing waveform can include pulse groupings that repeat at a group repetition period of greater than or equal to 1.5 μs. Each pulse of the pulse groupings can have a pulse width of less than or equal to 900 fs.

A photovoltaic cell can include a nitrogen-containing metal layer in contact with a semiconductor layer.

Systems and methods disclosed and contemplated herein relate to manufacturing thin film semiconductors. Resulting thin film semiconductors are particularly suited for applications such as flexible optoelectronics and photovoltaic devices. Broadly, methods and techniques disclosed herein include high-temperature deposition techniques combined with lift-off in aqueous environments. These methods and techniques can be utilized to incorporate thin film semiconductors into substrates that have limited temperature tolerances.

A perovskite-silicon tandem cell capable of absorbing solar radiation with energy lower than that of 1.12 eV, i.e., the bandgap of crystalline silicon—corresponding to the wavelength of 1100 nm. Ho.sup.3+ can absorb photons of wavelength range 1120 to 1190 nm, Tm.sup.3+, 1190 to 1260 nm, and Er.sup.3+, 1145 to 1580 nm, but up-conversion can be achieved using Ho.sup.3+, Tm.sup.3+, and Er.sup.3+-doped metal oxide, such as ZrO.sub.2, in perovskite-silicon tandem solar cells. Doped metal oxides, such as ZrO.sub.2 can also work as selective contacts. Such perovskite-silicon tandem structures can achieve over 30% solar energy conversion efficiency.

A photovoltaic device (100) can include an absorber layer (160). The absorber layer (160) can be doped p-type with a Group V dopant and can have a carrier concentration of the Group V dopant greater than 4×10.sup.15 cm.sup.−3. The absorber layer (160) can include oxygen in a central region of the absorber layer (160). The absorber layer (160) can include an alkali metal in the central region of the absorber layer (160). Methods for carrier activation can include exposing an absorber layer (160) to an annealing compound in a reducing environment (220). The annealing compound (224) can include cadmium chloride and an alkali metal chloride.

Embodiments of a photovoltaic device are provided herein. The photovoltaic device can include a layer stack and an absorber layer disposed on the layer stack. The absorber layer can include a first region and a second region. Each of the first region of the absorber layer and the second region of the absorber layer can include a compound comprising cadmium, selenium, and tellurium. An atomic concentration of selenium can vary across the absorber layer. The first region of the absorber layer can have a thickness between 100 nanometers to 3000 nanometers. The second region of the absorber layer can have a thickness between 100 nanometers to 3000 nanometers. A ratio of an average atomic concentration of selenium in the first region of the absorber layer to an average atomic concentration of selenium in the second region of the absorber layer can be greater than 10.

The present invention proposes a method to form a CdSeTe thin film with a defined amount of selenium and with a high quality. The method comprises the steps of providing a base substrate and of depositing a partial CdSeTe layer on a first portion of the base substrate. The step of depositing a partial CdSeTe layer is performed at least twice, wherein a predetermined time period without deposition of a partial CdSeTe layer on the first portion of the base substrate is provided between two subsequent steps of depositing a partial CdSeTe layer. The temperature of the base substrate and the CdSeTe layer already deposited on the first portion of the base substrate is controlled during the predetermined time period such that re-evaporation of Cd and/or Te from the CdSeTe layer already deposited takes place.

According to the embodiments provided herein, a photovoltaic device can include an absorber layer. The absorber layer can be doped p-type with a Group V dopant and can have a carrier concentration of the Group V dopant greater than 4×10.sup.15 cm.sup.−3. The absorber layer can include oxygen in a central region of the absorber layer. The absorber layer can include an alkali metal in the central region of the absorber layer. Methods for carrier activation can include exposing an absorber layer to an annealing compound in a reducing environment. The annealing compound can include cadmium chloride and an alkali metal chloride.

A photovoltaic device includes a substrate, a transparent conductive oxide, an n-type window layer, a p-type absorber layer and an electron reflector layer. The electron reflector layer may include zinc telluride doped with copper telluride, zinc telluride alloyed with copper telluride, or a bilayer of multiple layers containing zinc, copper, cadmium and tellurium in various compositions. A process for manufacturing a photovoltaic device includes forming a layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process includes forming an electron reflector layer over a p-type absorber layer.

A solar cell module includes a plurality of compound semiconductor solar cells each including a compound semiconductor substrate, a first electrode part on a front surface of the compound semiconductor substrate, an insulating substrate positioned at a back surface of the compound semiconductor substrate, a second electrode part positioned between the back surface of the compound semiconductor substrate and a front surface of the insulating substrate, and an insulating adhesive attaching the insulating substrate to the second electrode part; a conductive connection member electrically connecting two adjacent compound semiconductor solar cells to each other; a conductive adhesive attaching the conductive connection member to a corresponding electrode part of the compound semiconductor solar cell; a front substrate positioned on the compound semiconductor solar cells; and a back substrate positioned below the compound semiconductor solar cells.