Generation of Dense Lying Ga(As)Sb Quantum Dots for Efficient Quantum Dot Lasers

Abstract

Two different approaches are pursued to realize densely packed gallium (arsenic) antimonide (Ga(As)Sb) quantum dots (QDs) for efficient QD lasers. In the first method nano¬structures are realized by self-organization using mask-less dry-etching. GaSb cone structures are achieved with a maximum density of 1.2 ∙ 1011 cm-2. During etching a 5 nm thick amor¬phous Ga layer is formed, also the surface oxidizes immediately under atmosphere, and as a consequence the dots are optoelectronically inactive, thus no photoluminescence (PL) can be achieved. Several attempts are made to revoke these effects, but the nanostructures stay inactive. In the second approach self-assembled optoelectronically active GaAsSb QDs are grown on GaAs in Stranski-Krastanov mode. With these QDs efficient lasers are grown, exemplarily with an emission wavelength around 900 nm. In pulsed mode a minimum thres¬hold current density of jth = 121.7 A/cm2 and a maximum in differential quantum effi¬ciency of ηd = 0.66 are measured at T = 130 K. The internal quantum efficiency is ηi = 0.76 with internal losses of αi = 4.86 cm-1.

1 ML Wetting Layer upon Ga(As)Sb Quantum Dot (QD) Formation on GaAs Substrate Monitored with Reflectance Anisotropy Spectroscopy (RAS)

“…Very interesting results have been achieved by the Huffaker group [12][13][14][15], which brought the aerial density of antimonide QD to 290 m −2 . The authors of the current contribution have been successful in increasing the aerial QD density even further, i.e., to values of about 1000 m −2 , which lets the QD nearly abut in the growth plane [16][17][18][19][20]. E.g., dense lying QD are important to improve semiconductor laser efficiency.…”

“…There is less experience in the community with Ga(As)Sb (so-called antimonide) QD on GaAs substrate, but even in this regard quite a number of papers have been published (e.g., [4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]). Very interesting results have been achieved by the Huffaker group [12][13][14][15], which brought the aerial density of antimonide QD to 290 m −2 .…”

Epitaxial Growth of Optoelectronically Active Ga(As)Sb Quantum Dots on Al‐Rich AlGaAs with GaAs Capsule Layers

“…Inorganic quantum dots (QDs), especially concerning their potential use in semiconductor lasers, have been in the research focus for 25 years now [1,2]. In particular, Ga(As) Sb quantum dots (QDs) grown on GaAs [3][4][5][6][7][8][9][10][11][12][13] are of interest as an active material for efficient lasers in the near-and midinfrared. ese lasers could, for example, be used for sensitive spectroscopy or even long-distance optical communications via glass fibers [11].…”

High-crystalline GaSb epitaxial films grown on GaAs(001) substrates by low-pressure metal–organic chemical vapor deposition

“…In recent years, the research on antimonide semiconductors has made much progress, such as the applications in a monolithic microwave integrated circuit (MMIC), [1] infrared focal plane array detectors, [2] infrared lasers, [3] quantum-cascade lasers, [4] quantum-dot lasers, [5] quantumwell lasers, [6] thermoelectric devices, [7] thermophotovoltaic devices, [8,9] and resonant tunneling diodes. [10][11][12][13][14] Both GaSb and GaAs are III-V semiconductors, which have the same crystal structure and a type-II band alignment can be developed by the GaSb/GaAs heterostructure.…”