Properties of stacked SrTiO3/Al2O3 metal-insulator-metal capacitorsPhotoluminescence emanating from "pure" high resistivity SrTiO" has been examined between 4000 and 13 000 A as a function of temperature and 3650 A irradiation. One strong narrow peak: (7929 A at 95°K; half-width ~1 A) and 9 associated peaks (7852, 8005, 8051, 8098, 8280, 8304, 8469, 8574, 8726 A), each of which exhibit maximum intensity at 35° and 95°K, which are within the temperature ranges associated with the ferroelectric-paraelectric transition, and the tetragonal-cuhic transition, respectively. As this emission extinguishes below 35°K, an asymmetric structureless broadband emission begins, which extends from ""4200-,,,,8000 A, and peaks near 5000 A. Concurrent photocurrent measurements show: a maximum at 105°K and a minimum at 35°K; the existence of extensive trapping effects, including long-duration (hours to days) dark-current relaxation, a field-induced persistent internal polarization (due to spacial separation of trapped electrons and holes), and an interaction between irradiation and ferroelectric hysteresis. Sublinear responses exist common to the photoluminescence peaks and photocurrents at various temperatures, viz. response a:: J~(T) where ! <~ (T) < 1. The behavior ohserved is in part interpretable on the basis of recombination processes via multiple defects.

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Diffusion and sputtering techniques are described for applying low resistance, highly transparent, antireflecting, electrical contacts to CdS. The diffusion process entails heating CdS for several minutes in the presence of indium vapor. The resulting crystal surface resistance has been adjusted to range as low as 12 ohms/square without any observable crystal discoloration. The sputtering process employs an 82–18% indium-tin alloy that is placed onto the crystal surface using oxygen as the sputtering atmosphere. The resulting film is Sn-doped In2O3, measuring 100–150 ohms/square, and showing 80–100% transmittance from 4600 to 20 000 A.

Graphic means for fabricating active circuit elements have been examined in an exploratory program. Compatible and complementary semiconductor‐,dielectric‐, and metal‐inks have been developed and tested. Their use in various juxtaposed and overlayed configurations has produced operational insulated‐gate field‐effect transistors. The ultimate goal is to establish processes compatible with existing processes for silk‐screened resistors and capacitors and produce high‐volume, low‐cost active circuits. Four types of graphically produced transistors typically exhibit two characteristic modes of behavior; high transconductance false(≤2000µnormalmhosfalse) coupled with poor frequency response false(<100 normalcpsfalse) ; and low transconductance false(≤20µnormalmhosfalse) coupled with better frequency response false(>100 normalcpsfalse) . These behaviors correlate with gate‐dielectric parameters. Various organic and inorganic gate‐dielectric materials have been tested; best results to date have been obtained with nitrocellulose, silicate cement, glyceryl monostearate, or barium titanate in association with normalCdS:normalCdSe . Sintering of the semiconductor layer and postprocessing of the inks after each printing deposition have been found necessary to enhance device performance. The times involved with these operations are comparable to conventional screened conductor, resistor and capacitor processing periods.

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