Formation of mid-infrared emissive InAs quantum dots on a gradedInxGa1−xAs/InP matrix with a more uniform size and higher density under safer growth conditions

Abstract

InAs mid-infrared emissive quantum dots (QDs) grown on a gradedInxGa1−xAs/InP matrix with more uniform size and higher dot density have been successfully prepared by lowpressure metal organic chemical vapour deposition (LP-MOCVD) under safer growth conditions.Low toxic tertiarybutylarsine and tertiarybutylphosphine sources were used to replace the hightoxic arsine and phosphine in the MOCVD growth. To improve the process safety further, inertialN2 instead of the normallyused explosive H2 was used as the carrier gas. Initially, by using a two-step growth method, uniform InAs QDs with a high dotdensity of 1.3 × 1010 cm−2 have been successfully grown on a InGaAs/InP matrix. The emission wavelength of the QDs reaches>2.1 µm. The low temperature photoluminescence spectrum of the QDs grown by the two-stepgrowth has much narrower linewidth and higher intensity than that of the QDs grown byusing normal Stranski–Krastanow (S–K) and atomic layer epitaxy (ALE) growth methods.