A back-to-back diode includes a substrate having five superimposed layers of hydrogenated amorphous silicon thereon. The first and fifth layers are of one conductivity type, the second and fourth layers are intrinsic, and the third layer is of the opposite conductivity type. The layers are all of the substantially the same thickness. A conductive layer contact is provided between the substrate and the first layer and a conductive layer contact is provided on the fifth layer. The intrinsic layers may include carbon alloyed with the hydrogenated amorphous silicon.
The invention concerns an optoelectronic device comprising at alteration of at least three semiconductor layers with selected shape, and two air layers. The semiconductor layers having N-type or P-type doping which may differ or not from one layer to the next layer, are separated by spacers whereof the doping is non-intentional (I-type) or intentional (N-type or P-type) to define a PINIP or NIPIN structure with air cavities, and are adapted to be set at selected respective electric potentials. The respective thicknesses and compositions of the layers and the spacers are selected so that the structure has at least an optical transfer function adapted to light to be treated and adjustable in accordance with the selected potentials applied to the semiconductor layers.
An amorphous Si/SiC heterojunction color-sensitive phototransistor was successfully fabricated by plasma-enhanced chemical vapor deposition. The structure is glass/ITO/a-Si(n.sup.+ -i-p.sup.+)/a-SiC(i-n.sup.+)/Al. The device is a bulk barrier transistor with a wide-bandgap amorphous SiC emitter. The phototransistor revealed a very high optical gain of 40 and a response speed of 10 us at an input light power of 5 uW and a collector current of 0.12 mA at a voltage of 14 V. The peak response occurs at 610 nm under 1 V bias and changes to 420 and 540 nm under 7- and 13-V biases, respectively.
A diode which includes a first region formed in a polycrystalline silicon layer formed on a substrate. The diode has a predetermined width W and is one of an intrinsic region and a region including impurities at a low concentration therein, a second region and a third region including P-type impurities and N-type impurities therein respectively and both being oppositely arranged from each other with the first region therebetween in the polycrystalline silicon layer. Electrodes are electrically connected to the second region and the third region respectively, and further the film characteristic of the polycrystalline silicon layer and the predetermined width W thereof are determined in such a manner as to fulfill the following equation: L represents a carrier diffusion length and W.sub.D represents a width of the depletion layer created in the polycrystalline silicon layer when the voltage corresponding to the withstand voltage required by the polycrystalline diode as mentioned above, is applied thereto.
Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.
This invention is directed to a three-terminal semiconductor device which acts as a differential light detector. It is based on the operation of two reverse biased PIN photodetectors where one receives light through its P-doped surface and the other through its N-doped surface. The device is configured to be compatible with applications in integrated optics and with fiber optics. In principle of operation the invention relies on the production and collection of electrons from the detection of a first light intensity and the production and collection of holes from the detection of the intensity of a second light. This is done in a connected or integrated semiconductor which allows the recombination of electrons and holes. The excess number of electrons or holes, depending upon which light is received with the greatest intensity, is extracted from the recombination region and is the basis for the output signal.
