3 µm diode lasers grown on (Al)GaInSb compositionally graded metamorphic buffer layers

Abstract

Diode lasers operating at 3 μm in continuous wave mode at room temperature were fabricated using metamorphic molecular beam epitaxy. The laser heterostructures have a lattice constant 1.3-1.6% bigger than that of the GaSb substrates. The mismatch between the epi-structure and the substrate lattice constants was accommodated by a network of misfit dislocations confined within linearly compositionally graded buffer layers. Two types of the buffers were tested-GaInSb and AlGaInSb. The laser heterostructures with Al-containing buffer layers demonstrated better surface morphology and produced devices with lower threshold and higher efficiency. At the same time the use of Al-containing buffers caused an excessive voltage drop across the laser heterostructure. Thus, a maximum continuous wave output power of 200 mW was obtained from lasers grown on GaInSb buffers, while only 170 mW was obtained from those grown on AlGaInSb buffers.

Next-generation mid-infrared sources

“…Another recently developed approach involves the use of metamorphic (i.e. strain-relaxed) buffers on GaSb, to shift the lattice constant of the entire device while aiming to maintain low dislocation density [87]. The shift to a 1%-2% larger lattice constant platform (e.g.…”

Low-Temperature and Metamorphic Buffer Layers

“…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].…”

“…Linearly graded metamorphic buffers have been the widely used in device applications, including HEMTs [18,21,23,105,106,109,110,118,123,129,131,134,135], metal oxide semiconductor high electron mobility transistors (MOS HEMTs) [136], heterojunction bipolar transistors (HBTs) [113,117,118,137], LEDs [31,123], laser diodes [26,81,103,106,122], photodiodes [18,80,108,138,139], and solar cells [119]. Recent work with metamorphic HEMTs has emphasized In x Ga 1Àx As/In y Al 1Ày As quantum wells grown on GaAs (001) substrates by MBE [18,21,23,35,103,118,123,129,131,135].…”

Study and simulation of electron transport in Ga-=SUB=-0.5-=/SUB=-In-=SUB=-0.5-=/SUB=-Sb based on Monte Carlo method

“…Through time, investigations continued to growth up significantly going from simple GaInSb structures to more complexes heterostructure based electronic devices such as, laser diodes and transistors, etc. [4][5][6][7][8][9]. In fact, the features of this material include those of GaSb and InSb materials such as low direct band-gap (from 0.17 to 0.72 eV), high mobility (from 5000 to 80 000 cm 2 /Vs) and low effective masses (from 0.014 m e to 0.042 m e ) [10].…”