Effect of band alignment on photoluminescence and carrier escape from InP surface quantum dots grown by metalorganic chemical vapor deposition on Si

Journal Article · Tue Jan 28 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4862439· OSTI ID:22275668

Halder, Nripendra N. ^[1]; Biswas, Pranab; Dhabal Das, Tushar; Das, Sanat Kr.; Chattopadhyay, S. ^[2]; Biswas, D. ^[3]

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1. Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721 302 (India)
2. Department of Electronic Science, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009 (India)
3. Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721 302 (India)

A detailed analysis of photoluminescence (PL) from InP quantum dots (QDs) grown on Si has been carried out to understand the effect of substrate/host material in the luminescence and carrier escape process from the surface quantum dots. Such studies are required for the development of monolithically integrated next generation III-V QD based optoelectronics with fully developed Si microelectronics. The samples were grown by atmospheric pressure metalorganic chemical vapor deposition technique, and the PL measurements were made in the temperature range 10–80 K. The distribution of the dot diameter as well as the dot height has been investigated from atomic force microscopy. The origin of the photoluminescence has been explained theoretically. The band alignment of InP/Si heterostructure has been determined, and it is found be type II in nature. The positions of the conduction band minimum of Si and the 1st excited state in the conduction band of InP QDs have been estimated to understand the carrier escape phenomenon. A blue shift with a temperature co-efficient of 0.19 meV/K of the PL emission peak has been found as a result of competitive effect of different physical processes like quantum confinement, strain, and surface states. The corresponding effect of blue shift by quantum confinement and strain as well as the red shift by the surface states in the PL peaks has been studied. The origin of the luminescence in this heterojunction is found to be due to the recombination of free excitons, bound excitons, and a transition from the 1st electron excited state in the conduction band (e{sub 1}) to the heavy hole band (hh{sub 1}). Monotonic decrease in the PL intensity due to increase of thermally escaped carriers with temperature has been observed. The change in barrier height by the photogenerated electric-field enhanced the capture of the carriers by the surface states rather than their accumulation in the QD excited state. From an analysis of the dependence of the PL intensity, peak position, and line width with temperature and excitation source, the existence of free and bound excitonic recombination together with e{sub 1} → hh{sub 1} transitions in the QDs is established.

• OSTI ID: 22275668
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ATOMIC FORCE MICROSCOPY
CHEMICAL VAPOR DEPOSITION
ELECTRIC FIELDS
ELECTRONIC STRUCTURE
ELECTRONS
EXCITATION
EXCITED STATES
EXCITONS
HETEROJUNCTIONS
INDIUM PHOSPHIDES
LINE WIDTHS
PHOTOLUMINESCENCE
QUANTUM DOTS
RECOMBINATION
RED SHIFT
SILICON
SURFACES
TEMPERATURE RANGE 0013-0065 K