Terahertz Emission Mechanisms in III–V Semiconductors …
173
3 Isoelectronic Doping
Alloying is a common technique used to tailor the optoelectronic properties of a semiconductor so that it fits the desired application. The process involves the introduction
of new isoelectronic elements into the host material. Various isoelectronic species
that have characteristics like atomic radii, ionicity, and electronegativity, similar to
the host, are preferred. However, exceptions to this also exist. Isoelectronic alloying
in III–V semiconductors is one of the heavily investigated areas of semiconductor
sciences in the past decades [13, 14]. Such processes often drastically alter the structural, optoelectronic, and transport properties of the parent material. The interest in
these alloys is two-fold: scientific curiosities on the nature of perturbations that come
along with alloying as well as rich and diverse applications these alloys potentially
hold.
The introduction of isoelectronic species perturbs the host semiconductor bandstructure. As mentioned earlier, alloying is a tool to tune several material parameters.
One could easily see that tertiary alloys encompass a richer diversity of physical systems compared to binary systems. The introduction of new isoelectronic species
and its compositional variation generates material systems with a broad spectrum of
properties. The following are a few properties influenced and tuned by isoelectronic
compositional variation.
• Structural parameters like lattice parameters and crystallinity.
• Optoelectronic parameters like bandgap, spin–orbit splitting energy, and the
temperature sensitivity of bandgap.
• Transport properties like doping, electron–hole mobility.
Bandgap and lattice engineering of isoelectronic III–V alloys pushes its applicability
to the fabrication of hybrid solar cells, LEDs, and lasers [13–15].
The strong influence of isoelectronic alloying on the structural, optoelectronic,
and transport properties would inevitably modify the terahertz emission properties
also.
4 III–V Bismide Alloys
Bismuth is the heaviest stable member in group V. Bismuth sets itself apart from
the rest of the members with its highest atomic radius and lowest electronegativity. It acts as an isoelectronic substituent in III–V semiconductor systems. Bismuth
incorporation into many of these III–V systems brings distinct modifications to the
host semiconductors. Many of these characteristics have potential applications in the
fabrication of optoelectronic devices ranging from detectors to solar cells and lasers.
Some of the critical modifications introduced by Bi incorporation in III–V systems
are discussed below.
173
3 Isoelectronic Doping
Alloying is a common technique used to tailor the optoelectronic properties of a semiconductor so that it fits the desired application. The process involves the introduction
of new isoelectronic elements into the host material. Various isoelectronic species
that have characteristics like atomic radii, ionicity, and electronegativity, similar to
the host, are preferred. However, exceptions to this also exist. Isoelectronic alloying
in III–V semiconductors is one of the heavily investigated areas of semiconductor
sciences in the past decades [13, 14]. Such processes often drastically alter the structural, optoelectronic, and transport properties of the parent material. The interest in
these alloys is two-fold: scientific curiosities on the nature of perturbations that come
along with alloying as well as rich and diverse applications these alloys potentially
hold.
The introduction of isoelectronic species perturbs the host semiconductor bandstructure. As mentioned earlier, alloying is a tool to tune several material parameters.
One could easily see that tertiary alloys encompass a richer diversity of physical systems compared to binary systems. The introduction of new isoelectronic species
and its compositional variation generates material systems with a broad spectrum of
properties. The following are a few properties influenced and tuned by isoelectronic
compositional variation.
• Structural parameters like lattice parameters and crystallinity.
• Optoelectronic parameters like bandgap, spin–orbit splitting energy, and the
temperature sensitivity of bandgap.
• Transport properties like doping, electron–hole mobility.
Bandgap and lattice engineering of isoelectronic III–V alloys pushes its applicability
to the fabrication of hybrid solar cells, LEDs, and lasers [13–15].
The strong influence of isoelectronic alloying on the structural, optoelectronic,
and transport properties would inevitably modify the terahertz emission properties
also.
4 III–V Bismide Alloys
Bismuth is the heaviest stable member in group V. Bismuth sets itself apart from
the rest of the members with its highest atomic radius and lowest electronegativity. It acts as an isoelectronic substituent in III–V semiconductor systems. Bismuth
incorporation into many of these III–V systems brings distinct modifications to the
host semiconductors. Many of these characteristics have potential applications in the
fabrication of optoelectronic devices ranging from detectors to solar cells and lasers.
Some of the critical modifications introduced by Bi incorporation in III–V systems
are discussed below.