Infrared p-i-n photodiodes based on InAs quantum dots grown on 20 nm patterned GaAs

Abstract

We report on selective area growth of InAs quantum dots on GaAs substrates patterned with a hexagonal array of 20 nm pores using block copolymer lithography. We discuss the mechanisms of growth, highlighting the variation in the resulting morphology as a function of nucleation enhancing AlGaAs layers. We also evaluate the optoelectronic performance of p-i-n photodiodes based on single layer nanopatterned grown InAs quantum dot devices. At low to moderate reverse biases, we observe room temperature photoresponse in both near- and mid-IR regimes. At high biases, we observe strong avalanche effects in the mid-IR range with a gain factor of ∼4000.

Nanofabrication of III–V semiconductors employing diblock copolymer lithography

“…Low threshold current density patterned InGaAs QD active layer lasers on GaAs substrates were also reported by Elarde et al, employing e-beam lithographic patterning and MOCVD growth [64]. Implementation of MBE grown InAs QDs defined through diblock copolymer lithography into p-i-n photodiode devices structures was also recently reported by Alizadeh et al [81]. We discuss below the first application of nanopatterned QD active regions into diode laser structures on InP substrate.…”

“…After the semiconductor surface has been nanopatterned, various approaches have been used to form the QDs on either GaAs or InP substrates, such as nano-post etching of QW materials [72][73][74][75], selective growth using a dielectric mask [64,69,70,[76][77][78][79][80] or site-controlled growth [67,[81][82][83][84][85][86][87][88]. The formation of highly uniform nano-post (40 nm dia.)…”

“…If complete two-dimensional growth can be fully suppressed in the 'field' areas, then complete threedimensional carrier confinement can be achieved with the sitecontrolled growth process, without the formation of a wetting layer. Enhanced nucleation in the etched 'site regions' has been observed when employing the growth of an Al-containing layer prior to InAs deposition [81]. However, an inherent limitation of the site-controlled approach is that it is only applicable to the growth of highly strained QDs (i.e.…”

Growth behavior and defect reduction in heteroepitaxial InAs and GaSb on GaAs using block copolymer lithography

“…The growth of InAs and GaSb on nano-patterned templates exhibited few observed threading dislocations when compared to growth on non-patterned substrates. Twinning along the {1 1 1} planes is observed in both systems and may be eliminated by employing templates that do not involve the dielectric layer [9].…”

Nanostructures and Functional Materials Fabricated by Interferometric Lithography

“…At the nanometer‐scale, physical size is directly correlated with the electronic energy levels and, therefore, size fluctuations give rise to inhomogeneous broadening, which can impact devices. Various process technologies have been demonstrated mostly for InAs PQDs on GaAs: electron beam lithography,112, 113 block copolymer lithography,114 IL,99, 100, 111 electrochemical etching,115 and droplet epitaxy 116. The emphasis has been on isolated quantum dots, with one dot per lithograhically defined position.…”