OPTOELECTRONIC DEVICE COMPRISING A SEMICONDUCTOR LAYER BASED ON GeSn HAVING A SINGLE-CRYSTAL PORTION WITH A DIRECT BAND STRUCTURE AND AN UNDERLYING BARRIER REGION

An optoelectronic device for emitting or for receiving infrared radiation, comprising:

• cleation layer;
• a crystalline semiconductor layer comprising GeSn, extending in a main plane, having an upper face opposite to the nucleation layer, and comprising:
• a base portion, extending over and in contact with the nucleation layer;
• an upper portion, extending over the base portion, single-crystal, and under tensile stress with an average value ϵps in the main plane, composed of a homogeneous medium having a uniform value xps1 of atomic proportion of tin, the average value ϵps of the tensile stresses and the value xps1 of the atomic proportion of tin being such that the upper portion has a direct bandgap structure;
• a pin semiconductor junction, comprising a doped region of the n type and a doped region of the p type, flush with the upper face, and an intrinsic region situated within the upper portion and extending between the doped regions;
• metal polarizing contacts, situated on and in contact with the doped regions;
• wherein:
• the single-crystal upper portion comprises, aside from the homogeneous medium, vertical structures
• extending in the homogeneous medium along an axis orthogonal to the main plane over the whole thickness of the upper portion, and
• having an average value xps2 of atomic proportion of tin greater than xps1, thus forming regions for emitting or for receiving said infrared radiation;
• the semiconductor layer furthermore comprises an intermediate portion,
• situated between and in contact with the base portion and the upper portion along an axis orthogonal to the main plane,
• single-crystal, and
• comprising a region extending in the main plane over its whole width and having an average value xpi1 of atomic proportion of tin less than xps1, thus forming a barrier region against charge carriers flowing in the upper portion.