Light emitting semiconductor structure

Claim 2

Light emitting semiconductor structure consisting of a thin active layer, which layer at the underside passes to a further or not structured doped layer in direct contact with a first electrode, and which layer at the upperside passes into a further or not structured oppositely doped layer, in direct contact with a second electrode, which electrodes during operation of the structure are connected to a current source to generate a current of carriers through the light emitting semiconductor structure, characterized in that said upper layer comprises an inside barrier of which the permeability for carriers depends on the voltage applied to the third electrode which third electrode is positioned on the outside of said upper layer in the proximity of said second electrode.

Claim 3

Semiconductor structure according to claim 1, characterized in that the third electrode is positioned on the outside of the upper layer at some distance of the second electrode and the third electrode forms a Schottky-contact with said upper layer, whereby furthermore the barrier is embodied as an insulating layer inside said oppositely doped upper layer having an opening, whereby at least the edges of said barrier in the proximity of said opening are positioned close underneath that part of the surface of said upper layer where said third electrode is positioned such, that by means of the Schottky-zone generated underneath said third electrode in said upper layer when a control voltage is applied to said third electrode the carrier current between the first and the second electrode through the opening in said barrier is more or less cut off.

Claim 4

Semiconductor structure according to claim 1, characterized in that the third electrode is attached to the outside of the upper layer, electrically insulated from the semiconductor material of said layer and positioned at some distance of said second electrode, whereby said barrier is embodied as an insulating layer inside said oppositely doped upper layer, having an opening, whereby at least the edges of said barrier in the proximity of said opening are positioned close underneath that part of the surface of said upper layer where said third electrode is positioned such, that by means of a field generated by said third electrode when a control voltage is applied thereto the carrier current between the first and second electrodes through the opening in said barrier is more or less cut off.

Claim 5

Semiconductor structure according to claims 2 or 3, characterized in that the second electrode comprises an elongated electrode segment and elongated mutually parallel electrode fingers extending preferably approximately perpendicular to said elongated electrode segment, whereby the third electrode comprises a number of elongated electrode strips extending between the electrode fingers of said second electrode and said insulating barrier comprises a number of barrier segments positioned underneath the electrode fingers of said second electrode, whereby the intermediate openings between said barrier segments are positioned underneath the electrode strips of said third electrode.

Claim 6

Semiconductor structure according to claim 4, characterized in that each of the electrode strips of the third electrode can be connected to a separate control voltage source.

Claim 7

Semiconductor structure according to claim 1, characterized in that the third electrode is positioned inside said upper layer functioning also as barrier,which barrier has an opening of which the width is such that when a voltage lower than the avalanche voltage is applied the Schottky-barrier will extend so far around the third electrode that the opening into said electrode is completely closed.

Claim 8

Semiconductor structure according to claim 6, characterized in that the third electrode is embodied as a number of electrode strips, whereby the dimensions of the intermediate openings are fulfilling the above mentioned requirements.

Claim 9

Semiconductor structure according the claim 7, characterized in that, each of the electrode strips of the third electrode can be controlled independently by a separate control voltage source.

Claim 10

Semiconductor structure according to one of the preceding claims, characterized in that in said semiconductor structure a partly or completely photosensitive area is created adjoining the third electrode.

Claim 11

Semiconductor structure according to claim 9 having a Schottky-zone, characterized in that the Schottky-zone is made photosensitive into the opening or openings of the third electrode respectively underneath said third electrode.

Claim 12

Semiconductor structure according to claim 10, characterized in that the structure of the upper layer comprises a section extending above the second and third electrode, whereby the structure between said second and third electrode at least in the proximity of the third electrode has an absorption coefficient for inciding light which is smaller than the absorption coefficient of the surrounding semiconductor material.

Claim 13

Semiconductor structure according to claim 11, characterized in that the structure between the second and third electrode at least adjoining the third electrode has openings functioning as light channel.

Claim 14

Optical cable comprising a semiconductor structure according to one of the preceding claims.

Claim 15

System for detecting optically readible registered information comprising a semiconductor structure according to one of the preceding claims 1-12.

Claim 16

System for registration of optical information onto a suitable registration medium comprising a semiconductor structure according to one of the preceding claims 1-12.