Studies of GaAs photodiodes are described. It is shown that the introduction of a carboxylic acid monolayer between the GaAs and the Au top electrode can increase diode efficiency by up to a factor of 1.24. Further increases can be obtained by the introduction of two further layers using the Langmuir-Blodgett technique.

Infrared absorption spectra were measured in the spectral range 4000-200 cm-1 for the Cu20-Bi=O3 glass system. Strong bands were observed around 436-477, 600-632, 700-715, 810-875, 975-1000, 1550-1610 and 3225-3510 crn -1 which are due to harmonics of the Bi-O-Bi stretching vibration, Cu-O stretching vibrations, O-Bi-O stretching vibrations, O-Bi-O bending vibrations, Bi-O stretching vibrations, free H=O normal-mode bending vibrations and free H20 molecules or OH-ions, respectively. Quantitative justification of these absorption bands shows that the values of the experimental wave number for most recorded absorption bands agree well with the theoretical ones.The optical absorption spectra were recorded for the same glass system in the spectral range 300-700 nm. These records show that the absorption edge has a tail extending towards lower energies. The edge shifts towards lower energies with increasing Cu20 content. This shift is mostly related to the structural rearrangement and the relative concentrations of the glass basic units. By increasing the Cu20 content, the optical energy gap decreases, while the width of the localized states increases.

Studies of GaAs photodiodes are described in which insulating layers formed from amphiphilic polymers deposited by the Langmuir-Blodgett technique are incorporated. It is shown that it is possible, by using this technique, to increase the diode efficiency by a substantial amount and to form devices that are stable at temperatures in excess of 200 degrees C and that have considerable mechanical stability.