Proton implantation-induced intermixing of InAs∕InP quantum dots

Abstract

Proton implantation-induced intermixing of InAs quantum dots ͑QDs͒ capped with InP, GaInAsP, and InP and InGaAs layers grown by metal-organic chemical vapor deposition is investigated. The samples are annealed at 750, 800, 850, and 900°C for 30 s and thermal stability of the QDs is studied. The optimum annealing temperature is around 800°C which gives maximum implantation-induced energy shift. The QDs capped with InP layers show the highest implantation-induced energy shift due to strong group V interdiffusion whereas the QDs grown on and capped with GaInAsP layers show the least implantation-induced energy shift due to weak group V and group III interdiffusion. The QDs capped with InP and InGaAs layers show intermediate implantation-induced energy shift and are less thermally stable compared to the QDs grown on and capped with GaInAsP layers. The QDs capped with InP layers show enhanced photoluminescence ͑PL͒ intensity when implanted with lower proton dose ͑less than 5 ϫ 10 14 ions/ cm 2 ͒. On the other hand higher proton dose ͑more than 1 ϫ 10 14 ions/ cm 2 ͒ reduces the PL linewidth in all samples.

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

“…A large P implantation induced blue shift of up to 325 meV (~1.48 µm reference sample) was observed by Dion et al [88]. On the other hand, Barik et al [87] reported high proton implantation-induced energy blue shift due to strong group V interdiffusion, and the least blue shift from the Qdots capped with InGaAsP layer due to weak group V and group III interdiffusion. In addition, higher dose decreased the PL linewidth of the samples due to homogenization of Qdots as a result of interdiffusion which is shown in Fig.…”

“…This was attributed to the presence of a non-equilibrium concentration of point defects in the LT-InP which was confirmed by the progressive etching of this layer which led to the gradual quenching of the PL shift. The effect of the influence of post-growth phosphorus implantation [88,89] and proton-implantation [87] followed by RTA was carried out on the CBE and MOCVD grown InAs/(100)-InP Qdots with InP capping layer and with thin GaAs interlayer capped with InGaAs or InGaAsP capping layer. A large P implantation induced blue shift of up to 325 meV (~1.48 µm reference sample) was observed by Dion et al [88].…”

Effects of grown-in defects on interdiffusion dynamics in InAs∕InP(001) quantum dots subjected to rapid thermal annealing

“…To overcome this issue, different band gap tuning techniques have been proposed: optimization of growth parameters, [4][5][6][7] introduction of interface layers, 8,9 and postgrowth intermixing. [10][11][12][13][14][15][16] Intermixing is a thermally activated process that consists in atomic interdiffusion at the interface of materials with different alloy compositions. This process can be judiciously used to tune the emission properties of quantum heterostructures as it modifies their band gap and confinement profile, thus their corresponding energy levels.…”

“…10 The topic of locally enhanced interdiffusion has been receiving much attention since it can be used to finely tune the optoelectronic properties of heterostructures in specific regions of the sample for monolithic integration of planar waveguides 17 and optoelectronic components. 18 Enhanced intermixing during thermal treatment can be achieved through the localized creation or inclusion of point defects in the structure by using, for example, dielectric capping, 11 ion implantation, [12][13][14][15] or growth at reduced temperatures to introduce grown-in defects ͑GID͒. 16 Despite the success stories of these intermixing techniques, most of the work reported in literature have been essentially parametrical, demonstrating, for example, that a particular treatment can produce a certain amount of emission energy shift after annealing at a given temperature.…”

Disordering of Quantum Structures for Optoelectronic Device Integration

“…A thin GaAs interlayer also improves the thermal stability of the InAs/InP QDs. Figure 14 shows the schematic of three InAs QD structures with different buffer or capping layers of either InP or Ga 0.25 In 0.75 As 0.54 P 0.46 (Barik et al, 2006b) and Figure 15 shows the results of the thermal interdiffusion of these QD structures (with respect to the as-grown QDs) as a function of annealing temperature. In comparison, the QDs having the GaAs interlayer show less thermal energy shifts compared to the QDs without GaAs interlayer, particularly at higher annealing temperatures.…”