Polarization Doped Nanowire Devices as an Alternative to Impurity Doping
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Date
2013-03
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Abstract
It is difficult to control electrical conductivity in wide band gap semiconductors using impurity doping because of large ionization energies in these materials. Polarization-induced doping in compositionally graded heterostructures is a possible alternative to impurity doping in certain wide band gap materials. Here we present compositionally graded AlGaN nanowires grown on Si(111) substrates by plasma-assisted molecular beam epitaxy that utilize polarization-induced doping to form p-n junctions. GaN quantum wells are inserted into the nanowires to create polarization-induced nanowire light emitting diodes (PINLEDs) that emit ultraviolet light. Variable temperature electrical measurements show that dopants in the structure are ionized by polarization-induced charge and therefore do not freeze-out at cryogenic temperatures. Furthermore, electroluminescence measurements show that polarization-induced charge alone (i.e. with no intentionally added dopants) can be used to form working LEDs.
Description
Engineering: 2nd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)
Keywords
polarization-induced doping, III-nitrides, nanostructures, molecular beam epitaxy, light emitting diodes