InAs Nanostructures in a Silicon Matrix: Growth and Properties
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G.E. CIRLIN" 2 , V.A. EGOROV', V.N. PETROV', A.O. GOLUBOK1, N.I. KOMYAK',
N.K. POLYAKOV 1 '2 , YU.B. SAMSONENKO1, 2, D.V. DENISOV 2 , B.V. VOLOVIK 2, 2 23 V.M. USTINOV 2, Zh.I. ALFEROV , N.N. LEDENTSOV ' , R. HEITZ3 , D. BIMBERG3 , 4 4 4 GOSELE U. , WERNER N.D. ZAKHAROV , P. 2'Institute
for Analytical Instrumentation RAS, St.Petersburg, Russia A.F.Ioffe Physico-Technical Institute RAS, St.Petersburg, Russia 3Technical University, Berlin, Germany 4 Max-Plank-Institute for Microstructure Physics, Halle/Saale, Germany Tel: 007-812-2479350, Fax: 007-812-2517038, cirlin(a.beam.ioffe.rssi.ru ABSTRACT Under certain growth conditions InAs/Si heteroepitaxial growth proceeds via StranskiKrastanow or Volmer-Weber growth modes depending on the growth parameters. Critical thickness at which three dimensional InAs islands start to appear at the Si(100) surface is within the range of 0.7 - 4.0 monolayers (substrate temperature range is 350 0 C - 430 0 C). Their size depends critically on the growth conditions and is between 5 nm and 80 nm (uncapped islands). Critical lateral size of the coherent (Si capped) dislocation-free island is equal to 2 - 5 nm depending on the island height. Islands having larger size are dislocated. Optical properties of InAs nanoscale islands capped with Si reveal a luminescence band in the 1.3 gm region. INTRODUCTION Self-organisation effects at semiconductor surfaces during molecular beam epitaxy (MBE) attract strong interest during the last decade. In this direction the most attention was paid to the quantum dots (QDs) in I1I/V - I11/V (e.g., InAs - GaAs) [1,2], IL/VI - Il/VI (e.g., CdSe - ZnSe) [3]
or IV - IV (Si - Ge) [4] materials systems. The last system attracted much efforts because silicon remains a key material in modem microelectronics industry. For optoelectronic applications silicon is not well suitable because of its indirect band gap nature. Attempts to improve the situation using SiGe-Si QDs did not led to significant progress as these nanostructures provide indirect band alignment both in k- and in real space. In order to increase luminescence efficiency of silicon-based structures we propose to insert direct bandgap InAs QDs in a Si matrix using MIBE growth [5]. We emphasize that this approach is different from the growth utilizing InAs QDs on thick GaAs buffers [6]. Small coherent InAs islands additionally offers a possibility to overcome the problems of strong lattice mismatch and formation of antiphase domains inherent for the growth of thick III-V epilayers (e.g. GaAs) on Si. In this paper we report on the MBE growth and properties of the InAs nanoscale islands formed on silicon. We have found that under certain growth conditions InAs/Si heteroepitaxial growth proceeds via Stranski-Krastanow or Volmer-Weber growth modes depending on the growth parameters leading to the formation of nanoscale islands. The lateral size depends critically on the growth conditions and is in the range of 2 - 80 nm. Optical properties of InAs QDs capped with Si reveal a luminescence band in the 1.3 l
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