Optical Properties of InAs Quantum Dots Grown on InP (001) Substrate by MOCVD

Abstract

We report on the optical properties of InAs self-organized quantum dots formed in an InP matrix by low-pressure metal organic chemical vapour deposition (MOCVD) using TBAs and TBP as group-V sources. Strong photoluminescence located at wavelength $1.3 mm is observed at room temperature. The photoluminescence taken at low temperatures shows multiple peaks. Some of the peaks are attributed to emission from different low-dimensional structures.Among a variety of fabrication techniques developed for the realization of high quality quantum dots, the fabrication of coherently strained self-organized quantum dots (SQDs) deposited by heteroepitaxial growth in the Stranski-Krastanov mode has attracted much attention since these defect-free, zero-dimensional, semiconductor structures are expected to lead to major developments for future high-speed electronic and optoelectronic devices as well as for their intriguing physical properties [1]. The SQDs formation process is driven by the reduction of the total strain and surface energy of the layer-substrate system and is limited by kinetic factors such as adatom migration and surface diffusion [2, 3]. So far, most studies have focused on InAs SQDs in GaAs and InP SQDs in GaInP. In contrast, relatively few reports are available regarding the growth of InAs SQDs in InP. In view of the strong luminescence of the SQDs at about 1.3-1.55 mm, which makes the InAs SQDs in InP well suited for optoelectronic communication devices, e.g., lasers with a low threshold current, high modulation speed, and temperature insensitivity, a detailed understanding of their optical properties is of great interest. It has been demonstrated that the mean size of the InAs dots on InP surface is about 30-70 nm [4,5], which is larger than that formed on GaAs surface, and the emission wavelength of the SQDs is around the region of 1.5 mm [4][5][6][7][8]. In addition, differing from a GaAs surface, it has been shown that As/P exchange reaction plays an important role in the formation of InAs SQDs on the InP surface [9][10][11]. Especially, InAs dots can be formed on InP surface by only using the As/P exchange reaction [9,12].In this paper, we report on the results of the optical properties of InAs SQDs which are grown in InP by MOCVD using TBA and TBP as group V sources. The emission at about 1.3 mm has been observed at room temperature.The growth is performed in a low-pressure MOCVD system with a horizontal reactor, using trimethylindium (TMIn), trimethylgallium (TMGa), pure TBA and TBP as source materials. The structures are grown on a (001) InP substrate. After the substrate treatment at 650 C for 5 min under TBP, an InP buffer layer with a thickness of 200 nm is grown at 600 C. The substrate temperature is then lowered to 450 C under 1 ) Fax: (65) 8720785;

Growth and characterization of InAs on (100) InP ultrathin single quantum wells using tertiarybutylarsine and tertiarybutylphosphine

“…7,8 Scientific reasons include the investigation of the extent of As-P intermixing during growth, the study of the wetting layer prior to the formation of quantum dots in the Stranski-Krastanov growth mode, 9,10 and the validity of the envelope function approximation and tight-binding calculations for the description of the electronic states in ultrathin wells. Technological reasons include a high radiative efficiency, a moderately high misfit ͑3.2%͒ and a potential for applications such as quantum well lasers.…”