# US 5,351,256 A · Electrically injected visible vertical cavity surface emitting laser diodes

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- Number: US 5,351,256 A
- Document ID: US5351256A
- Status: Granted
- Kind: A
- Application number: 08/055,178
- Filed: 1993-04-28
- Granted: 1994-09-27
- Earliest claimed: 1993-04-28
- Assignees: The United States of America as represented by the United States Department of Energy
- Inventors: Richard P. Schneider; James A. Lott
- Web page: https://patentgrep.com/patent/US5351256A

## CPC

- H01S 5/18361: {Structure of the reflectors, e.g. hybrid mirrors}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- H01S 5/18358: {containing spacer layers to adjust the phase of the light wave in the cavity}
- H01S 5/3211: {characterised by special cladding layers, e.g. details on band-discontinuities}
- H01S 5/34326: {with a well layer based on InGa(Al)P, e.g. red laser}
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

Visible laser light output from an electrically injected vertical cavity surface emitting laser (VSCEL) diode is enabled by the addition of phase-matching spacer layers on either side of the active region to form the optical cavity. The spacer layers comprise InAlP which act as charge carrier confinement means. Distributed Bragg reflector layers are formed on either side of the optical cavity to act as mirrors.

## Claims

### Claim 1

An electrically injected vertical cavity laser diode for emitting light at a visible wavelength comprising:
a III-V compound substrate of a first conductivity type connected to a first electrode;
a first multiplicity of distributed Bragg reflectors (DBRs) being of the first conductivity type formed above the substrate;
an optical cavity formed above the first DBRs and comprising a first optical phase matching spacer layer located adjacent the first DBRs and of the same conductivity, an active region having an active lasing means located adjacent to and above the first spacer layer, and a second optical phase matching spacer layer adjacent to and above the active region and of the opposite conductivity type from the first spacer layer, wherein each spacer layer has a thickness of between one wavelength and three wavelengths of the emitted light;
a second multiplicity of distributed Bragg reflectors (DBRs) of the opposite conductivity type formed above the optical cavity; and
a second electrode means located above the active region.

### Claim 2 (depends on 1)

The laser of claim 1 wherein the optical phase-matching layers have higher bandgaps than the materials comprising the active lasing means.

### Claim 3 (depends on 1)

The laser of claim 1 wherein the optical phase-matching layers comprise materials which optimize charge carrier injection efficiency into the active region.

### Claim 4 (depends on 1)

The laser of claim 1 wherein the optical phase-matching layers comprise AlInP.

### Claim 5 (depends on 1)

The laser of claim 1 wherein the active lasing means comprises at least one quantum well.

### Claim 6 (depends on 5)

The laser of claim 5 wherein the active lasing means comprises at least one strained quantum well.

### Claim 7 (depends on 6)

The laser of claim 6 wherein the active lasing means further comprises lattice-matched barrier means on either side of the at least one strained quantum well.

### Claim 8 (depends on 7)

The laser of claim 7 wherein various components of the active lasing means comprise InAlGaP compounds.

### Claim 9 (depends on 8)

The laser of claim 8 wherein the composition of the InAlGaP compounds is defined as In.sub.x (Al.sub.y Ga.sub.1-y).sub.1-x P, where 0.ltoreq.y.ltoreq.1.

### Claim 10 (depends on 1)

The laser of claim 1 wherein the active lasing means comprises a bulk semiconductor material.

### Claim 11

An electrically injected vertical cavity laser diode for emitting light at a visible wavelength comprising:
a III-V compound substrate of a first conductivity type connected to a first electrode;
a first multiplicity of distributed Bragg reflectors (DBRs) being of the first conductivity type formed above the substrate;
an optical cavity formed above the first DBRs and comprising an active region having at least one strained quantum well surrounded by lattice-matched barrier means, a first optical phase matching spacer layer located adjacent the first DBRs and of the same conductivity, and a second optical phase matching spacer layer on the other side of the active region and of the opposite conductivity type, wherein each spacer layer has a thickness of between one wavelength and three wavelengths of the emitted light and the optical phase matching layers have higher bandgaps than the materials comprising the DBR's;
a second multiplicity of distributed Bragg reflectors (DBRs) of the opposite conductivity type formed above the optical cavity; and
a second electrode means, such that the second electrode means has an opening within it for the transmission of the laser light output.

### Claim 12 (depends on 11)

The laser of claim 11 wherein the optical phase-matching layers have higher bandgaps than the materials comprising the at least one strained quantum well and the surrounding lattice-matched barrier means.

### Claim 13 (depends on 11)

The laser of claim 11 wherein the optical phased-matching layers comprise AlInP.

### Claim 14 (depends on 11)

The laser of claim 11 wherein the active region is at least one wavelength thick.

### Claim 15 (depends on 11)

The laser of claim 11 wherein various components of the at least one strained quantum well and the surrounding lattice-matched barrier means comprise InAlGaP compounds.

### Claim 16 (depends on 15)

The laser of claim 15 wherein the composition of the InAlGaP compounds is defined as In.sub.x (Al.sub.y Ga.sub.1-y).sub.1-x P, wherein 0.ltoreq.y.ltoreq.1.

### Claim 17

An electrically injected vertical cavity laser diode for emitting light at a visible wavelength comprising:
a III-V compound substrate of a first conductivity type connected to a first electrode;
a first multiplicity of distributed Bragg reflectors (DBRs) being of the first conductivity type formed above the substrate;
an optical cavity formed above the first DBRs and comprising a first optical phase matching spacer layer located adjacent the first DBRs and of the same conductivity, an active region having an active lasing means located adjacent to and above the first spacer layer, and a second optical phase matching spacer layer adjacent to and above the active region and of the opposite conductivity type form the first spacer layer, wherein each spacer layer is an integral multiple of .lambda./4n in thickness where .lambda. is the wavelength and n is the refractive index of the spacer and the total thickness of the optical cavity is an integral multiple of .lambda./2n;
a second multiplicity of distributed Bragg reflectors (DBRs) of the opposite conductivity type formed above the optical cavity; and
a second electrode means located above the active region.

### Claim 18 (depends on 17)

The laser of claim 17 wherein the optical phase-matching layers have higher bandgaps than the materials comprising the active lasing means.

### Claim 19 (depends on 17)

The laser of claim 17 wherein the optical phase-matching layers comprise AlInP.

### Claim 20 (depends on 17)

The laser of claim 17 wherein the active lasing means comprises at least one quantum well.

### Claim 21 (depends on 17)

The laser of claim 17 wherein the active lasing means comprises at least one strained quantum well.

### Claim 22 (depends on 17)

The laser of claim 17 wherein various components of the active lasing means comprise InAlGaP compounds.

### Claim 23 (depends on 22)

The laser of claim 22 wherein the composition of the InAlGaP compounds is defined as In.sub.x (Al.sub.y Ga.sub.1-y).sub.1-x P, where 0.ltoreq.y.ltoreq.1.

### Claim 24 (depends on 17)

The laser of claim 17 wherein the active lasing means comprises a bulk semiconductor material.