A photovoltaic cell may include a hydrogenated amorphous silicon layer including a n-type doped region and a p-type doped region. The n-type doped region may be separated from the p-type doped region by an intrinsic region. The photovoltaic cell may include a front transparent electrode connected to the n-type doped region, and a rear electrode connected to the p-type doped region. The efficiency may be optimized for indoor lighting values by tuning the value of the H2/SiH4 ratio of the hydrogenated amorphous silicon layer.

The present invention relates to the epitaxial lift-off of thin-films allowing the reuse of the expensive semiconductor substrates. In particular, it describes a structure and a method for epitaxial lift-off of several thin films from a single substrate (100) using a plurality of dissimilar sacrificial layers (101), strained layers (102, 104), and/or device or component layers (103). The properties of the sacrificial layers (101) and the strained layers (102,104) can be used (i) to facilitate the lift off process, (ii) to control the point of time of release of each released thin film individually and (iii) to aid in separation and sorting of the released thin films. The released device or component layers can comprise various useful structures, such as optoelectronic devices photonic components.

A method for thermal exfoliation includes providing a target layer on a substrate to form a structure. A stressor layer is deposited on the target layer. The structure is placed in a temperature controlled environment to induce differential thermal expansion between the target layer and the substrate. The target layer is exfoliated from the substrate when a critical temperature is achieved such that the target layer is separated from the substrate to produce a standalone, thin film device.

A method for forming a back contact on an absorber layer in a photovoltaic device includes forming a two dimensional material on a first substrate. An absorber layer including CuZnSnS(Se) (CZTSSe) is grown over the first substrate on the two dimensional material. A buffer layer is grown on the absorber layer on a side opposite the two dimensional material. The absorber layer is exfoliated from the two dimensional material to remove the first substrate from a backside of the absorber layer opposite the buffer layer. A back contact is deposited on the absorber layer.

The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

A handle substrate having at least one metallization region is provided on a stressor layer that is located above a base substrate such that the at least one metallization region is in contact with a surface of the stressor layer. An upper portion of the base substrate is spalled, i.e., removed, to provide a structure comprising, from bottom to top, a spalled material portion of the base substrate, the stressor layer and the handle substrate containing the at least one metallization region in contact with the surface of the stressor layer.

The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

A handle substrate having at least one metallization region is provided on a stressor layer that is located above a base substrate such that the at least one metallization region is in contact with a surface of the stressor layer. An upper portion of the base substrate is spalled, i.e., removed, to provide a structure comprising, from bottom to top, a spalled material portion of the base substrate, the stressor layer and the handle substrate containing the at least one metallization region in contact with the surface of the stressor layer.

This work provides a new approach for epitaxial liftoff. Instead of using a sacrificial layer that is selectively etched chemically, the sacrificial layer selectively absorbs light that is not absorbed by other parts of the structure. Under sufficiently intense illumination with such light, the sacrificial layer is mechanically weakened, melted and/or destroyed, thereby enabling epitaxial liftoff. The perimeter of the semiconductor region to be released is defined (partially or completely) by lateral patterning, and the part to be released is also adhered to a support member prior to laser irradiation. The end result is a semiconductor region removed from its substrate and adhered to the support member.

A semiconductor structure includes a thin-film device layer, an optoelectronic device disposed in the thin-film device layer, and a surrogate substrate permanently attached to the thin film device layer. The surrogate substrate is optically transparent and has a thermal conductivity of at least 300 W/m-K. The optoelectronic device excitable by visible light transmitted through the surrogate substrate. A method of fabricating the semiconductor structure includes fabricating the optoelectronic device in a device layer thin-film of SiC on a silicon wafer of a first diameter, transferring the device layer thin-film of SiC from the silicon wafer, and permanently bonding the device layer thin-film to a SiC surrogate substrate of a second diameter.