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Vertical and Lateral Mid‐Infrared Photocurrent Study on Ge Quantum Dots in Si
Author(s) -
Miesner C.,
Brunner K.,
Abstreiter G.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200103)224:2<605::aid-pssb605>3.0.co;2-v
Subject(s) - photocurrent , responsivity , quantum dot , photoconductivity , materials science , infrared , germanium , optoelectronics , infrared detector , doping , condensed matter physics , photodetector , molecular physics , optics , physics , silicon
In this paper we discuss photocurrent measurements in normal incidence geometry performed on self‐assembled Ge dots in Si. The “classical” detector concept with vertical photocurrent is compared to a new one which is based on in‐plane photoconductivity and is only realizable with dots. The active region of the samples consists of ten layers of Ge dots formed by self‐assembly in the Stranski‐Krastanov growth mode with lateral dimensions of about 20 nm and a height of about 1.5 nm. The mid‐infrared photocurrent measurements show the typical line shape of bound‐to‐continuum transitions. The responsivity of the lateral device of 10 mA/W is about twice that of the vertical structure, furthermore the peak maximum at 284 meV is shifted by about 40 meV towards smaller energies. This is explained using a model involving carrier transfer to the modulation doping layer.