InGaAs/AlInAs strain-compensated Superlattices grown on metamorphic buffer layers for low-strain, 3.6μm-emitting quantum-cascade-laser active regions

Low-Temperature and Metamorphic Buffer Layers

“…Step-graded buffers have been investigated in a number of material systems including In x Ga 1Àx As [27,28,[66][67][68][69], In x Al 1Àx As [24,39,68,[70][71][72][73][74][75][76][77][78][79][80], In x Al y Ga 1ÀxÀy As [19,35,80], and Al x Ga 1Àx Sb y As 1Ày [52,81] on GaAs (001) substrates, InAs y P 1Ày [29,[82][83][84] on InP (001), and In x Al 1Àx Sb [85] on GaSb (001).…”

“…Step-graded buffers have been successfully applied in device applications including HEMTs [20,35,[71][72][73][74], QD lasers [27,81], quantum cascade lasers [19], and thermovoltaic cells [84].…”

“…Buffer layers with linearly-graded composition, and therefore lattice constant, have been extensively investigated in a number of material systems, including In x Ga 1Àx As/GaAs [25,26,51,[96][97][98][99][100][101][102][103][104], In x Al 1Àx As/GaAs [34,75,103,[105][106][107][108][109][110], In x Al y Ga 1ÀxÀy As/GaAs [18,19,23,35,80,95,111], Si 1Àx Ge x /Si [112][113][114][115][116], In x Ga 1Àx P/GaAs [117][118][119], In x Ga 1Àx P/ GaP [120], ZnS y Se 1Ày /GaAs [102,121], and In x Ga 1Àx Sb/GaSb [122,123]. A possible advantage of continuous grading is that layer-by-layer growth may be maintained without the intrusion of island growth associated with large, abrupt changes in composition [119].…”

Interface Intermixing in Type II InAs/GaInAsSb Quantum Wells Designed for Active Regions of Mid-Infrared-Emitting Interband Cascade Lasers

“…The first, based on type I quantum well structures, is limited to below 4 μm due to the accessible band gaps and band offsets in a combination of quaternary GaInAsSb and quinary AlGaInAsSb alloys of GaSb-based devices [2,3]. The second type are quantum cascade lasers (QCLs) which require substantial band discontinuity in the conduction band of the active quantum wells [4,5] making the fabrication challenging, with the additional drawback of large threshold currents and high power consumption. In that respect, the idea to employ the so-called interband cascade lasers (ICLs) [6] utilizing type II InAs/GaInSb quantum wells in the active region [7,8] is very promising.…”

Threading Dislocations in S-Graded ZnSxSe1-x/GaAs (001) Metamorphic Buffer Layers

“…Metamorphic devices which have been fabricated on lattice-mismatched substrates include InGaAs/InAlAs HEMTs on GaAs, 3 InGaAs/InAlAs heterojunction bipolar transistors (HBTs) on GaAs, 4 InGaAs/InP HEMTs and HBTs on GaAs, 5 InAlAs photodiodes on GaAs, 6 InAsSb/AlInAsSb light-emitting diodes (LEDs) on GaSb, 7 AlInGaAsSb laser diodes on GaSb, 8 InGaAs/InAlGaAs laser diodes on GaAs, 9 InGaAsSb/InAlAs quantum cascade laser structures on GaAs, 10 and InAlAs solar cells on GaAs. 11 Most work has focused on linearly-graded buffer layers, [2][3][4][5][6][7][8][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] while there have been several reports of the use of step-graded buffer layers 12,[31][32][33][34] or buffer layers with T. Kujofsa continuous, but non-linear grading of composition.…”