Abstract: A hetero-junction bipolar phototransistor includes a photo-absorption layer formed of a first conductivity type semiconductor layer, and a collector operating as a barrier layer, a base layer, and an emitter layer, which are stacked in sequence on the photo-absorption layer. The photo-absorption layer, collector, base layer and emitter layer forms a first mesa structure, and an emitter contact layer forms a second mesa structure. The photo-absorption layer includes a semiconductor layer with a narrow gap corresponding to a light-sensing wavelength of the phototransistor. The collector includes a semiconductor layer with a wider gap than a gap of the photo-absorption layer. The base layer has an energy level equal to or higher than the energy level of the collector. The emitter layer has a wide gap as compared to the base layer, and an energy level in a valence band is lower than an energy level of the base layer.

Abstract: An array structure solves issues that exist in conventional compound semiconductor photodiode arrays, such as large cross talk, large surface leaks, large stray capacitance, narrow detection wavelength bands, and bad manufacturing yield, simultaneously. A photodiode array has, laminated upon a semiconductor substrate, a buffer layer (8) with a broad forbidden band width, an I-type (low concentration photosensitive layer (2) with a narrow forbidden band width, and an n-type semiconductor window layer (3) with a broad forbidden band width, wherein photodiode elements are electrically separated from adjacent elements, by doping the periphery of the p-type impurity, and the detection wavelength band is expanded, by making the n-type window layer (3) on the photosensitive layer (2) a thinner layer with crystal growth.

Abstract: An array structure solves issues that exist in conventional compound semiconductor photodiode arrays, such as large cross talk, large surface leaks, large stray capacitance, narrow detection wavelength bands, and bad manufacturing yield, simultaneously. A photodiode array has, laminated upon a semiconductor substrate, a buffer layer (8) with a broad forbidden band width, an I-type (low concentration photosensitive layer (2) with a narrow forbidden band width, and an n-type semiconductor window layer (3) with a broad forbidden band width, wherein photodiode elements are electrically separated from adjacent elements, by doping the periphery of the p-type impurity, and the detection wavelength band is expanded, by making the n-type window layer (3) on the photosensitive layer (2) a thinner layer with crystal growth.

Abstract: The present invention provides a HPT having high sensitivity and extensive wavelength band characteristics. The collector and barrier layer (5) is formed on the photo-absorption layer (6), wherein the energy level in the conduction band is higher than that of the photo-absorption layer (6), the energy level in the valence band is almost equal to or higher than that of the photo-absorption layer (6) and is a relatively wider gap semiconductor than the photo-absorption layer. The base layer (4) formed on the collector and barrier layer (5), is a relatively narrow gap as compared with the collector and barrier layer (5), wherein the energy level in the conduction band is equal to or higher than that of the collector and barrier layer (5) in the boundary of the collector and barrier layer (5).

Abstract: A detector for detecting the acceleration, the velocity or the displacement of a point is described. The detector includes a light source, at least two photoelectric elements spaced apart from each other over a predetermined distance and a focusing optical system disposed between the light source and the photoelectric elements; the combination being particularly suited for use as an optical seismic detector for detecting and mapping an underground stratum structure.

Abstract: A semiconductor photodiode comprising an N+ InP substrate 6, a similar InP substrate layer 7, an N- InGaAs layer 8, a thin N-type InP layer 9, an N- InP layer 10 and a P+ InP region 11 forming the top of the photodiode. When reversed biased, the high electric field at the hetero-junction between the N- InGaAs and the N-type InP cause holes to tunnel through the band-gap difference barrier thereby eliminating slow trapping states at the hetero-interface.

Abstract: A fuel level detector for an automobile fuel tank comprises a strut vertically provided within a fuel tank, a float slidably fitted around the strut and having a permanent magnet therein, a plurality of magnetic induction type reed switches slantedly disposed along the strut with a adequate distance between the adjacent reed switches, the length of which distance being defined such that the permanent magnet of the float always actuates two adjacent reed switches simultaneously, a plurality of resistances respectively connected to the plurality of reed switches for changing current value according to the reed switches which are actuated, a residual quantity warning means having an element of a luminous body which is connected between a ground and a predetermined reed switch among the plurality of reed switches, and a distance retention mechanism for keeping constant a distance between the predetermined reed switch and the bottom surface of the fuel tank and having a guide mounted to a base member for verticall

Abstract: A semiconductor laser of the rib guide type having the thickness of an active layer within a stripe-shaped region thicker than that of the outside, and thus the stripe-shaped region is made to have a waveguide action and, thereby, fundamental mode laser may be achieved.

Abstract: A semiconductor laser device in which at least one of the main surfaces of a semiconductor laser crystal body which generates heat during operation is brought into thermal contact with a silicon crystal heat-sink body.