Bulk AlInAs on InP(111) as a novel material system for pure single photon emission

In this letter, we report on quantum light emission from bulk AlInAs grown on InP(111) substrates. We observe indium rich clusters in the bulk Al0:48In0:52As (AlInAs), resulting in quantum dot-like energetic traps for charge carriers, which are confirmed via cross-sectional scanning tunnelling microscopy (XSTM) measurements and 6-band k•p simulations. We observe quantum dot (QD)-like emission signals, which appear as sharp lines in our photoluminescence spectra at near infrared wavelengths around 860 nm, and with linewidths as narrow as 50 meV. We demonstrate the capability of this new material system to act as an emitter of pure single photons as we extract g(2)-values as low as g(2)/cw (0) = 0:05+0:17/-0:05 for continuous wave (cw) excitation and g (2) pulsed, corr. = 0:24 ± 0:02 for pulsed excitation.PostprintPeer reviewe

Probing the local electronic structure of isovalent Bi atoms in InP

Cross-sectional scanning tunneling microscopy (X-STM) is used to experimentally study the influence of isovalent Bi atoms on the electronic structure of InP. We map the spatial pattern of the Bi impurity state, which originates from Bi atoms down to the sixth layer below the surface, in topographic, filled state X-STM images on the natural $\{110\}$ cleavage planes. The Bi impurity state has a highly anisotropic bowtie-like structure and extends over several lattice sites. These Bi-induced charge redistributions extend along the $\left\langle 110\right\rangle$ directions, which define the bowtie-like structures we observe. Local tight-binding calculations reproduce the experimentally observed spatial structure of the Bi impurity state. In addition, the influence of the Bi atoms on the electronic structure is investigated in scanning tunneling spectroscopy measurements. These measurements show that Bi induces a resonant state in the valence band, which shifts the band edge towards higher energies. This is in good agreement to first principles calculations. Furthermore, we show that the energetic position of the Bi induced resonance and its influence on the onset of the valence band edge depend crucially on the position of the Bi atoms relative to the cleavage plane

Structural properties of Bi containing InP films explored by cross-sectional scanning

\u3cp\u3eThe structural properties of highly mismatched III-V semiconductors with small amounts of Bi are still not well understood at the atomic level. In this chapter, the potential of cross-sectional scanning tunneling microscopy (X-STM) to address these questions is reviewed. Special attention is paid to the X-STM contrast of isovalent impurities in the III-V system, which is discussed on the basis of theoretical STM images of the (110) surface using density functional theory (DFT) calculations. By comparing high-resolution X-STM images with complementary DFT calculations, Bi atoms down to the third monolayer below the InP (110) surface are identified. With this information, the Short-range ordering of Bi is studied, which reveals a strong tendency toward Bi pairing and clustering. In addition, the occurrence of Bi surface segregation at the interfaces of an InP/InP\u3csub\u3e1−x\u3c/sub\u3eBi\u3csub\u3ex\u3c/sub\u3e/InP quantum well with a Bi concentration of 2.4 % is discussed.\u3c/p\u3

Structural Properties of Bi Containing InP Films Explored by Cross-Sectional Scanning

The structural properties of highly mismatched III-V semiconductors with small amounts of Bi are still not well understood at the atomic level. In this chapter, the potential of cross-sectional scanning tunneling microscopy (X-STM) to address these questions is reviewed. Special attention is paid to the X-STM contrast of isovalent impurities in the III-V system, which is discussed on the basis of theoretical STM images of the (110) surface using density functional theory (DFT) calculations. By comparing high-resolution X-STM images with complementary DFT calculations, Bi atoms down to the third monolayer below the InP (110) surface are identified. With this information, the Short-range ordering\ua0of Bi is studied, which reveals a strong tendency toward Bi pairing and clustering. In addition, the occurrence of Bi surface segregation\ua0at the interfaces of an InP/InP1−xBix/InP quantum well with a Bi concentration of 2.4 % is discussed

Structural properties of Bi containing InP films explored by cross-sectional scanning

The structural properties of highly mismatched III-V semiconductors with small amounts of Bi are still not well understood at the atomic level. In this chapter, the potential of cross-sectional scanning tunneling microscopy (X-STM) to address these questions is reviewed. Special attention is paid to the X-STM contrast of isovalent impurities in the III-V system, which is discussed on the basis of theoretical STM images of the (110) surface using density functional theory (DFT) calculations. By comparing high-resolution X-STM images with complementary DFT calculations, Bi atoms down to the third monolayer below the InP (110) surface are identified. With this information, the Short-range ordering of Bi is studied, which reveals a strong tendency toward Bi pairing and clustering. In addition, the occurrence of Bi surface segregation at the interfaces of an InP/InP1−xBix/InP quantum well with a Bi concentration of 2.4 % is discussed

Scanning tunneling microscopy contrast of isovalent impurities on the GaAs (110) surface explained with a geometrical model

Theoretical scanning tunneling microscopy (STM) images for all group-III and -V dopants on the GaAs (110) surface are calculated using density functional theory (DFT). In addition, a geometrical model based on the covalent radii of the dopants and substrate atoms is used to interpret the images. We find that the covalent radius of the dopant determines the geometry of the surface, which in turn determines the contrast seen in the STM images. Our model allows bond lengths to be predicted with an error of less than 4.2% and positions to be predicted with an average deviation of only 0.19 Å compared to positions from fully relaxed DFT. For nitrogen we demonstrate good qualitative agreement between simulated and experimental STM images for dopants located in the first three surface layers. We are able to explain differences in both the contrast and positions of bright and dark features in the STM image based on our geometrical model. We then provide a detailed quantitative analysis of the positions of the bright features for nitrogen dopants in the second layer. The agreement of the DFT calculation with experiment is excellent, with the positions of the peaks in simulated and experimental STM scans differing by less than 2% of the lattice constant. For dopants other than nitrogen, we compare the calculated STM image contrast with the available experimental data and again find good agreement