The present disclosure provides techniques for epitaxial oxide materials, structures and devices. In some embodiments, an integrated circuit includes a field effect transistor (FET) and a waveguide coupled to the FET, wherein the waveguide comprises a signal conductor. The FET can include: a substrate comprising a first oxide material; an epitaxial semiconductor layer on the substrate, the epitaxial semiconductor layer comprising a second oxide material with a first bandgap; a gate layer on the epitaxial semiconductor layer, the gate layer comprising a third oxide material with a second bandgap, wherein the second bandgap is wider than the first bandgap; and electrical contacts. The electrical contacts can include: a source electrical contact coupled to the epitaxial semiconductor layer; a drain electrical contact coupled to the epitaxial semiconductor layer; and a first gate electrical contact coupled to the gate layer.

A micro-LED chip includes multiple micro-LEDs. At least one micro-LED of the multiple micro-LEDs includes: a first type conductive layer; a second type conductive layer stacked on the first type conductive layer; and a light emitting layer formed between the first type conductive layer and the second type conductive layer. The light emitting layer is continuously formed on the whole micro-LED chip, the multiple micro-LEDs sharing the light emitting layer. The micro-LED chip further includes: a top spacer formed on a top surface of the light emitting layer; a bottom spacer formed on a bottom surface of the light emitting layer; and an isolation structure formed between adjacent micro-LEDs.

A micro-LED chip includes multiple micro-LEDs. At least one micro-LED of the multiple micro-LEDs includes: a first type conductive layer; a second type conductive layer stacked on the first type conductive layer; and a light emitting layer formed between the first type conductive layer and the second type conductive layer. The light emitting layer is continuously formed on the whole micro-LED chip, the multiple micro-LEDs sharing the light emitting layer. The micro-LED chip further includes: a top spacer formed on a top surface of the light emitting layer; a bottom spacer formed on a bottom surface of the light emitting layer; and an isolation structure formed between adjacent micro-LEDs.

A micro light emitting diode (LED) structure, includes a mesa structure. The mesa structure further includes a first semiconductor layer having a first conductive type, a light emitting layer formed on the first semiconductor layer, a second semiconductor layer formed on the light emitting layer, the second semiconductor layer having a second conductive type different from the first conductive type, a sidewall protective layer formed on the sidewalls of the mesa structures, and a sidewall reflective layer formed on the surface of the sidewall protective layer. The second semiconductor layer further includes a semiconductor region and an ion implantation region formed around the semiconductor region, the ion implantation region having a resistance higher than a resistance of the semiconductor region.

A micro light emitting diode (LED) structure, includes a mesa structure. The mesa structure further includes a first semiconductor layer having a first conductive type, a light emitting layer formed on the first semiconductor layer, a second semiconductor layer formed on the light emitting layer, the second semiconductor layer having a second conductive type different from the first conductive type. The second semiconductor layer further includes a semiconductor region and an ion implantation region formed around the semiconductor region, the ion implantation region having a resistance higher than a resistance of the semiconductor region.

A micro-LED structure includes: a first type conductive layer; a second type conductive layer stacked on the first type conductive layer; and a light emitting layer formed between the first type conductive layer and the second type conductive layer. The light emitting layer extrudes along a horizontal level away from a top edge of the first type conductive layer and a bottom edge of the second type conductive layer, such that an edge of the light emitting layer does not contact the top edge of the first type conductive layer and the bottom edge of the second type conductive layer. A profile of the second type conductive layer perpendicularly projected on a top surface of the first type conductive layer is surrounded by the top edge of the first type conductive layer.

A micro-LED structure includes: a first type conductive layer; a second type conductive layer stacked on the first type conductive layer; and a light emitting layer formed between the first type conductive layer and the second type conductive layer. The light emitting layer extrudes along a horizontal level away from a top edge of the first type conductive layer and a bottom edge of the second type conductive layer, such that an edge of the light emitting layer does not contact the top edge of the first type conductive layer and the bottom edge of the second type conductive layer. A profile of the second type conductive layer perpendicularly projected on a top surface of the first type conductive layer is surrounded by the top edge of the first type conductive layer.

A light emitting device includes a backplane, an array of light emitting diodes attached to a frontside of the backplane, a positive tone, imageable dielectric material layer, such as a positive photoresist layer, located on the frontside of the backplane and laterally surrounding the array of light emitting diodes, such that sidewalls of the light emitting diodes contacting the positive tone, imageable dielectric material layer have a respective reentrant vertical cross-sectional profile, and at least one common conductive layer located over the positive tone, imageable dielectric material layer and contacting the light emitting diodes.

A light-emitting element includes a first semiconductor layer doped to a first conductivity type, an active layer disposed on the first semiconductor layer, a second semiconductor layer disposed on the active layer, the second semiconductor layer doped to a second conductivity type, and a passivation layer surrounding surfaces of the active layer, the passivation layer including a side surface of the active layer, and the passivation layer includes a semiconductor material that matches a lattice of a semiconductor material contained in the active layer, the semiconductor material has a band gap energy higher than that of the semiconductor material contained in the active layer.

A light-emitting device includes a backplane, a light emitting diode (LED) emitter attached to the backplane, the LED emitter comprising an LED emitting stack that is made of a semiconductor material, and comprises an n-type region and a p-type region and a quantum well therebetween, and a light-reflecting partition attached to the backplane, wherein the light-reflecting partition is made of the semiconductor material, the light-reflecting partition forms a cavity surrounding the LED emitter, and a surface of the light-reflecting partition is coated with a first reflective layer.