In this review article a comprehensive analysis of the developments in ultraviolet (UV) detector technology is described. At the beginning, the classification of UV detectors and general requirements imposed on these detectors are presented. Further considerations are restricted to modern semiconductor UV detectors, so the basic theory of photoconductive and photovoltaic detectors is presented in a uniform way convenient for various detector materials. Next, the current state of the art of different types of semiconductor UV detectors is presented. Hitherto, the semiconductor UV detectors have been mainly fabricated using Si. Industries such as the aerospace, automotive, petroleum, and others have continuously provided the impetus pushing the development of fringe technologies which are tolerant of increasingly high temperatures and hostile environments. As a result, the main efforts are currently directed to a new generation of UV detectors fabricated from wide band‐gap semiconductors the most promising ...

Semiconductor ultraviolet detectors

In developing photovoltaic devices with high efficiencies, quantitative determination of the carrier loss is crucial. In conventional solar-cell characterization techniques, however, photocurrent reduction originating from parasitic light absorption and carrier recombination within the light absorber cannot be assessed easily. Here, we develop a general analysis scheme in which the optical and recombination losses in submicron-textured solar cells are evaluated systematically from external quantum efficiency (EQE) spectra. In this method, the optical absorption in solar cells is first deduced by imposing the anti-reflection condition in the calculation of the absorptance spectrum, and the carrier extraction from the light absorber layer is then modeled by considering a carrier collection length from the absorber interface. Our analysis method is appropriate for a wide variety of photovoltaic devices, including kesterite solar cells [Cu2ZnSnSe4, Cu2ZnSnS4, and Cu2ZnSn(S,Se)4], zincblende CdTe solar cells, and hybrid perovskite (CH3NH3PbI3) solar cells, and provides excellent fitting to numerous EQE spectra reported earlier. Based on the results obtained from our EQE analyses, we discuss the effects of parasitic absorption and carrier recombination in different types of solar cells.

Quantitative determination of optical and recombination losses in thin-film photovoltaic devices based on external quantum efficiency analysis

Current–voltage characteristics and quantum efficiency spectra of efficient thin-film CdS/CdTe solar cells

Recently, ultraviolet photoelectronics emerged in response to the needs of medicine, biology, military equipment, and the problem of the hole in the ozone layer. A specific feature of this field of photoelectronics is the need to detect weak (albeit appreciably affecting vital human functions) signals against a background of intense radiation in the visible and infrared regions of the spectrum. Ultraviolet electronics relies on Si-based p-n structures and GaP-based Schottky barriers, p-n structures and Schottky barriers based on GaN and AlGaN (“solar-blind,” i.e., solar-radiation-insensitive devices), SiC structures with potential barriers (high-temperature devices), and ZnO-and ZnS-based photoresistors and Schottky diodes. In this review, the parameters of starting wide-gap semiconductors are given, physical foundations for photoelectric conversion and the principles of formation of ohmic contacts are described, characteristics of corresponding devices are given, and the envisaged lines of further studies are outlined.

Semiconductor photoelectric converters for the ultraviolet region of the spectrum

Dependence of efficiency of thin-film CdS/CdTe solar cell on parameters of absorber layer and barrier structure

A detailed analytical calculation of the photoelectric quantum yield in Schottky diodes is presented. The transport of carriers in the surface space charge region is treated explicitly, taking account of photogeneration, diffusion and drift in the non-uniform electric field. Boundary conditions at the interface are expressed in terms of surface recombination velocity and emission velocity of excess carriers into the metal. It is shown that the metal-semiconductor interface strongly affects the collection efficiency of short wavelength generated electron-hole pairs. This effect basically originates in the emission flux of majority carriers into the metal. Current, charge carriers distributions and quantum yields are computed using the data of AuCdTe Schottky barriers.

Y. Marfaing

Papers

Theoretical analysis of the quantum photoelectric yield in schottky diodes