Novel materials and device design by metal-organic chemical vapor deposition for use in infrared emitters

The authors have grown AlSb and AlAs{sub x}Sb{sub 1{minus}x} epitaxial layers by metal-organic chemical vapor deposition(MOCVD) using trimethylamine or ethyldimethylamine alane, triethylantimony and arsine. These layers were successfully doped p- or n-type using diethylzinc or tetraethyltin, respectively. They examined the growth of AlAs{sub x}Sb{sub 1{minus}x} using temperatures of 500 to 600 C, pressures of 65 to 630 torr, V/III ratios of 1--17, and growth rates of 0.3 to 2.7 {micro}m/hour in a horizontal quartz reactor. They have also grown gain-guided, injection lasers using AlAsSb for optical confinement and a strained InAsSb/InAs multi-quantum well active region using MOCVD. The semi-metal properties of a p-GaAsSb/n-InAs heterojunction were utilized as a source for injection of electrons into the active region of the laser. In pulsed mode, the laser operated up to 210 K with an emission wavelength of 3.8--3.9 {micro}m. The dependence of active region composition on wavelength was determined. They also report on the 2-color emission of a light-emitting diode with two different active regions to demonstrate multi-stage operation of these devices

Recent Advances in Mid-Infrared (3--6 Micron) Emitters

The authors describe the metal-organic chemical vapor deposition (MOCVD) of InAsSb/InAs multiple quantum well (MQW) and InAsSb/InAsP strained-layer superlattice (SLS) active regions for use in mid-infrared emitters. They have made gain-guided, injection lasers using undoped, p-type AlAs{sub 0.16}Sb{sub 0.84} for optical confinement and both strained InAsSb/InAs MQW and InAsSb/InAsP SLS active regions. The lasers and LEDs utilize the semi-metal properties of a p-GaAsSb/n-InAs heterojunction as a source for electrons injected into active regions. A multiple-stage LED utilizing this semi-metal injection scheme is reported. Gain-guided, injected lasers with a strained InAsSb/InAs MQW active region operated up to 210 K in pulsed mode with an emission wavelength of 3.8--3.9 {micro}m and a characteristic temperature of 29--40 K. They also present results for both optically pumped and injection lasers with InAsSb/InAsP SLS active regions. The maximum operating temperature of an optically pumped 3.7 {micro}m SLS laser was 240 K. An SLS LED emitted at 4.0 {micro}m with 80 {micro}W of power at 300 K

Novel Mid-Infrared Lasers With Compressively Strained InAsSb Active Regions

Mid-infrared lasers grown by MOCVD with AlAsSb claddings and strained InAsSb active regions are reported. A 3.8--3.9 {micro}m injection laser with a pseudomorphic InAsSb multiple quantum well active region lased at 210 K under pulsed operation. A semi-metal layer acts as an internal electron source for the injection laser. An optically pumped laser with an InAsSb/InAsP strained-layer superlattice active region was demonstrated at 3.7 {micro}m, 240 K

The growth and doping of Al(As)Sb by metal-organic chemical vapor deposition

AlSb and AlAs{sub x}Sb{sub 1{minus}x} epitaxial films grown by metal-organic chemical vapor deposition were successfully doped p- or n-type using diethylzinc or tetraethyltin, respectively. AlSb films were grown at 500 C and 76 torr using trimethylamine or ethyldimethylamine alane and triethylantimony. The authors examined the growth of AlAsSb using temperature of 500 to 600 C, pressures of 65 to 630 torr, V/III ratios of 1--17, and growth rates of 0.3 to 2.7 {micro}m/hour in a horizontal quartz reactor. SIMS showed C and O levels below 2 {times} 10{sup 18} cm{sup {minus}3} and 6 {times} 10{sup 18} cm{sup {minus}3} respectively for undoped AlSb. Similar levels of O were found in AlAs{sub 0.16}Sb{sub 0.84} films but C levels were an order of magnitude less in undoped and Sn-doped AlAs{sub 0.16}Sb{sub 0.84} films. Hall measurements of AlAs{sub 0.16}Sb{sub 0.84} showed hole concentrations between 1 {times} 10{sup 17} cm{sup {minus}3} to 5 {times} 10{sup 18} cm{sup {minus}3} for Zn-doped material and electron concentrations in the low to mid 10{sup 18} cm{sup {minus}3} for Sn-doped material. They have grown pseudomorphic InAs/InAsSb quantum well active regions on AlAsSb cladding layers. Photoluminescence of these layers has been observed up to 300 K

The Growth of InAsSb/InAsP Strained-Layer Superlattices for Use in Infrared Emitters

We describe the metal-organic chemical vapor deposition growth of InAsSb/InAsP strained-layer superlattice (SLS) active regions for use in mid-infrared emitters. These SLSs were grown at 500{degrees}C, and 200 torr in a horizontal quartz reactor using TMIn, TESb, AsH{sub 3},and PH{sub 3}. By changing the layer thickness and composition we have prepared structures with low temperature ({le}20K) photoluminescence wavelengths ranging from 3.2 to 4.4 {mu}m. Excellent performance was observed for an SLS LED and both optically pumped and electrically injected SLS lasers. An optically pumped, double heterostructure laser emitted at 3.86 {mu}m with a maximum operating temperature of 240 K and a characteristic temperature of 33 K. We have also made electrically injected lasers and LEDs utilizing a GaAsSb/InAs semi-metal injection scheme. The semi-metal injected, broadband LED emitted at 4 {mu}m with 80 {mu}W of power at 300K and 200 mA average current. The InAsSb/InAsP SLS injection laser emitted at 3.6 gm at 120 K

Cross-Sectional Scanning Tunneling Microscopy of InAsSb/InAsP Superlattices

Cross-sectional scanning tunneling microscopy has been used to characterize compositional structure in InAs{sub 0.87}Sb{sub 0.13}/InAs{sub 0.73}P{sub 0.27} and InAs{sub 0.83}Sb{sub 0.17}/InAs{sub 0.60}P{sub 0.40} strained-layer superlattice structures grown by metal-organic chemical vapor deposition. High-resolution STM images of the (110) cross section reveal compositional features within both the InAs{sub x}Sb{sub 1{minus}x} and InAs{sub y}P{sub 1{minus}y} alloy layers oriented along the [{bar 1}12] and [1{bar 1}2] directions--the same as those in which features would be observed for CuPt-B type ordered alloys. Typically one variant dominates in a given area, although occasionally the coexistence of both variants is observed. Furthermore, such features in the alloy layers appear to be correlated across heterojunction interfaces in a manner that provides support for III-V alloy ordering models which suggest that compositional order can arise from strain-induced order near the surface of an epitaxially growing crystal. Finally, atomically resolved (1{bar 1}0) images obtained from the InAs{sub 0.87}Sb{sub 0.13}/InAs{sub 0.73}P{sub 0.27} sample reveal compositional features in the [112] and [{bar 1}{bar 1}2] directions, i.e., those in which features would be observed for CuPt-A type ordering

Intracavity frequency doubling of an optically-pumped, external-cavity surface-emitting semiconductor laser

The authors have produced milliwatts of blue light from a diode-pumped, multiple-quantum-well semiconductor laser. This compact source has a pump-to-blue optical efficiency >1%