EVAPORATED AND RECRYSTALLIZED CDS LAYERS.
Abstract
Heat treatments of evaporated CdS layers in nitrogen containing HC and traces of oxygen, and providing a transport of CdS and copper are reported. Recrystallization of areas up to several sq mm are observed. At 25C, the treated layers show mobilities of 140 to 230 sq cm/Vs, photoconductivities of 0.001 to 0.2/ohms/cm at 750 ft-c (2600K white light) with light-to-dark-current ratios of 10 to the 8th power - 10 to the 9th power and response time (decay) of 300 microsic to 1.2 ms at 100 ft-c. The level distribution and capture cross section for electrons is investigated using spectral distribution, light intensity, and temperature dependence of photoconductivity, thermally stimulated current and response time analyses. Levels at 0.23, 0.43, 0.67, 1.05 and 2.05 eV are observed and the letter three attributed to Cu-centers. Compared to other layers and single crystals, these layers show a density of <10 to the 12th power/cu cm of levels attributed to sulfur vacancies in the range between 0.3 and 0.65 eV and a not detectable amount of intrinsic defects acting as quenching centers at 0.9 and 1.35 eV. This is explained by a Cu-enhanced recrystallization in a CdS-supplying atmosphere at temperatures (620 to 650C) below the temperatures otherwise used for crystal growth, and thereby efficient annealing of intrinsic defects. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 27, 1966
- Accession Number
- AD0637725
Entities
People
- Karl Wolfgang Boer
Organizations
- University of Delaware