Fabrication of GaNAs/AlGaAs Heterostructures with Large Band Offset Using Periodic Growth Interruption

Abstract

We studied the growth of GaNAs/AlGaAs heterostructures on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. By introducing periodic growth interruption and nitrogen (N) supply to the interrupted surfaces during the growth of GaNAs, we achieved high controllability of the average N concentration in GaNAs layers. We observed three-dimensional island growth of GaNAs on the N-rich surfaces. The GaNAs island structures exhibit narrow photoluminescence emission at around 1 µm at low temperature, indicating the formation of a large band offset between GaNAs and AlGaAs.

Direct visualization of the N impurity state in dilute GaNAs using scanning tunneling microscopy

“…Nitrogen (N) doped III-V compounds have attracted attention due to their unique electronic properties, including large band gap reduction [1][2][3][4][5][6][7] and emission of extremely narrow band width luminescence from the N impurity center. [8][9][10][11][12] These distinctive properties have been considered to be induced by the interaction between the N impurity states and/or between the N impurity states and electronic states of the host semiconductor.…”

Effects of rapid thermal annealing on two-dimensional delocalized electronic states of the epitaxial N δ-doped layer in GaAs

“…For the as-grown sample, the PL peak energy exhibited a quadratic shift below the field intensity of 3 T, which indicates that electronic states are localized in the N d-doped layer in GaAs. 13 Conversely, a clear linear shift appeared above the field intensity of 3.5 T. This so-called 'Landau shift' represents magnetic quantization of the delocalized energy states and is attributed to the cyclotron motion in the growth plane. 13 This Landau shift signals the 2D delocalization of the electronic states in the N d-doped layer.…”

“…13 Conversely, a clear linear shift appeared above the field intensity of 3.5 T. This so-called 'Landau shift' represents magnetic quantization of the delocalized energy states and is attributed to the cyclotron motion in the growth plane. 13 This Landau shift signals the 2D delocalization of the electronic states in the N d-doped layer. On the other hand, for the sample annealed at 650 C, the PL peak energy exhibited the Landau shift obviously starting from $0 T, implying that the electronic states in this case are perfectly delocalized in the (001) plane.…”

“…8 N d-doping is an effective technique allowing control of the N-pair configuration [9][10][11] and engineering of the band structure. 12,13 In the impurity limit, N pair centers in GaAs act as isoelectronic traps below the conduction-band edge because of a strong electronegativity of N atoms. 9,[14][15][16] The electronic state of the localized impurity level is uniquely determined by the N pair structure in GaAs, thereby electronic coupling among high-density N pair centers enables to form a quasi epitaxial sheet.…”

Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs

“…Up to now, only few studies have tried to elucidate the properties of this promising material system. 21,22 Furthermore, by embedding GaNAs in AlGaAs it becomes possible to investigate the absorption characteristics of GaNAs QWs over a wide spectral range including higher energies which in previous studies of bulk GaNAs or GaNAs/GaAs QWs fall into the conduction and valance band continuum and are therefore hidden under the large density of states of the bands.…”