In the field of photoelectric devices, a visible light detector is provided with high-photoresponse based on a TiO.sub.2/MoS.sub.2 heterojunction and a preparation method thereof. The detector, based on a back-gated field-effect transistor based on MoS.sub.2, includes a MoS.sub.2 channel, a TiO.sub.2 modification layer, a SiO.sub.2 dielectric layer, Au source/drain electrodes and a Si gate electrode, The TiO.sub.2 modification layer is modified on the surface of the MoS.sub.2 channel. By employing micromechanical exfoliation and site-specific transfer of electrodes, the method is intended to prepare a detector by constructing a back-gated few-layer field-effect transistor based on MoS.sub.2, depositing Ti on the channel surface, and natural oxidation.

A contact to a semiconductor layer in a light emitting structure is provided. The contact can include a plurality of contact areas formed of a metal and separated by a set of voids. The contact areas can be separated from one another by a characteristic distance selected based on a set of attributes of a semiconductor contact structure of the contact and a characteristic contact length scale of the contact. The voids can be configured to increase an overall reflectivity or transparency of the contact.

The invention provides a beam intensity/positioning monitor substrate comprising a first metal foil in physical contact with a second metal foil. Also provided is a method for determining mass absorption coefficients, the method comprising measuring the absorption of an incident radiation beam by a first metal and a second metal comprising a bi-metal foil as a function of a first energy and a second energy; calculating the relative first metal thickness; using the relative thickness as a target value for the first metal fitting procedure; repeat the above steps on a free standing first metal foil; using the free standing first metal absorption measurements, bulk first metal density and first (bimetal) fit coefficients to determine first metal foil thickness; using free standing first metal to conduct a high resolution scan from just below its absorption edge to 1 keV or higher in energy; and using the free standing first metal absorption measurements below the absorption edge and experimentally determined thickness to compute mass absorption coefficients below its absorption edge.

A solar cell includes a light-absorbing layer, comprising a Cu compound or Cd compound, between two electrodes facing each other, has an impurity material layer, comprising an impurity element to be provided to the Cu compound or Cd compound, formed on any one side or both sides between the two electrodes and the light absorbing layer, and has a doping layer formed on one part of the light absorbing layer by means of the impurity element being diffused on the light absorbing layer.

A contact to a semiconductor layer in a light emitting structure is provided. The contact can include a plurality of contact areas formed of a metal and separated by a set of voids. The contact areas can be separated from one another by a characteristic distance selected based on a set of attributes of a semiconductor contact structure of the contact and a characteristic contact length scale of the contact. The voids can be configured to increase an overall reflectivity or transparency of the contact.