TY  - THES
AU  - Kamil, Sladek
TI  - Realization of III-V semiconductor nano structures towards more efficient (opto-) electronic devices
PB  - RWTH Aachen
VL  - Dr.
CY  - Jülich
M1  - FZJ-2014-00577
SP  - 100
PY  - 2013
N1  - RWTH Aachen, Diss., 2013
AB  - Solid state electronics and their application in personal computers, smartphones, digital
AB  - cameras and entertainment devices (to name a few) have gained such a rapid progress that
AB  - it’s already barely imaginable how our future technological environment will evolve in the next
AB  - few years. In parallel, however, concerns about excessive use of the world’s limited natural
AB  - energy resources has led to a rethinking with respect to the design and production of future
AB  - electronics.
AB  - One of the most promising solutions to further improve the efficiency of electronics is the
AB  - combination of the well established silicon technology with III-V semiconductor nano structures
AB  - which have been extensively investigated in various fields for the last few decades. InAs nano
AB  - structures, in particular, are intrinsically conductive due to their characteristic conduction band
AB  - profile, caused by surface states. The materials high bulk carrier mobility gives rise to expect a
AB  - significant boost in efficiency of electronic devices that employ InAs nano structures.
AB  - In this work, three different aspects of device improvement are addressed: the exchange of
AB  - channel material in traditional CMOS, the development of new nanostructure based concepts
AB  - and the use of direct band gap properties for more cost-effective sensing devices. The
AB  - established SA MOVPE of III-V nano structures on III-V substrates serves as a starting point.
AB  - Systematic experiments are conducted in order to address several significant questions
AB  - regarding the suitability of III-V nano structures as building blocks for future electronic devices.
AB  - It is found that a large variety of free-standing InAs nanowires with different properties can be
AB  - produced in an ordered and controlled fashion. The results show that uniform InAs nanowires
AB  - with a high aspect ratio can be produced selectively on GaAs(111)B and GaAs(110) oriented
AB  - surfaces, the latter being also a natural cleaved edge direction of industrially used Si(001)
AB  - substrates. In addition, very thin InAs nanowires with diameters down to 20 nm are obtained
AB  - as a side effect on non-structured cleaved-edge sidewalls of GaAs(001). N-type doping with
AB  - disilane is found to have a general impact on the nanowire morphology, resulting in a reduced
AB  - height vs. diameter aspect ratio with an increased amount of doping applied during deposition.
AB  - It is observed that all wires exhibit an intrinsic conductivity with an ohmic behavior which is
AB  - further increased after doping. Also, the nanowire diameter is found to be a potential
AB  - parameter to tune their electronic properties. A series of experiments with different growth
AB  - parameters and the successive characterization of the nanowires‘ crystal structure reveal that
AB  - different group-V partial pressures affect the formation of stacking faults and the crystal‘s
AB  - wurtzite to zinc blende ratio. A significant step to combine the gained knowledge on controlled
AB  - bottom-up InAs nanowire fabrication and benefits of SA MOVPE in N2 ambient with current
AB  - silicon technology is the transition of InAs growth to silicon substrates. The technique of flow
AB  - modulated epitaxy is adopted from MOVPE growth in hydrogen ambient and adapted and
AB  - optimized for growth in N2 in order overcome the lack of polarity on silicon. As a result, InAs
AB  - nanowire growth on Si(111) is carried out with a high yield of vertical wires.
AB  - After the investigation of free standing InAs nanowires mainly for concepts exceeding
AB  - CMOS, a methodology for the deposition of lateral InAs nano structures on silicon by SA
AB  - MOVPE was presented, aimed towards the exchange of channel material in current planar
AB  - electronic devices. Growth parameters adopted from GaAs/InAs core-shell nanowire growth
AB  - are applied to a variety of differently oriented and patterned substrates. The obtained lateral
AB  - structures are characterized with respect to morphology, crystal structure and electronic
AB  - properties. High crystallinity and conductivity are found and discussed in comparison to the
AB  - results obtained from vertical nanowires.
AB  - Finally, quantum cascade structures based on ternary III-V semiconductors with high indium
AB  - content are investigated with respect to single mode emission for gas sensing applications. It
AB  - is found that curved laser waveguides are capable of single mode emission which is explained
AB  - by the interaction of coupled cavities, resulting in strong side mode suppression. The
AB  - monolithic approach without need for complicated sample processing has tremendous
AB  - potential for the fabrication of cost effective and portable gas sensing devices.
KW  - Dissertation (GND)
LB  - PUB:(DE-HGF)11
UR  - https://juser.fz-juelich.de/record/150523
ER  -