Study of the Electronic Structure of Individual Free-Standing Germanium Nanodots Using Spectroscopic Scanning Capacitance Microscopy

Abstract

High spatial resolution spectroscopic scanning capacitance microscopy (SCM) measurements at room temperature based on the differential capacitance (d C=d V ) versus probe tip-to-substrate bias characteristics, is directly used to characterize the electronic structure of a pyramidal and an ellipsoidal shaped germanium (Ge) nanodot (with physical sizes smaller than the Bohr exciton radius of Ge), among the arrays of Ge nanodots fabricated on a highly doped silicon substrate using an anodic alumina membrane as an evaporation mask. The ability to study the individual nanodots under the probe tip circumvents and isolates the statistical disorders encountered when studying large ensembles of size-dispersed nanodots. It is demonstrated that the spectra of the positive d C=dV peaks are reflective of the energetics of electron trapping in the quantized energy states inside the Ge nanodots. Furthermore, the spectroscopic SCM d C=dV profile is observed to be substantially influenced by the nanodot shape where the pyramidal Ge nanodot shows three distinct shells which are interpreted as the s-like ground state, the first excited p-like state and the second excited d-like state. On the other hand, the elliptical deformation of the ellipsoidal Ge nanodot breaks the shell structure which significantly affects its electronic structure. Using the spacing between the d C=d V peaks from the spectroscopic SCM measurements, an analytical expression is derived to calculate the energy separation between the different energy states in the Ge nanodots. #

Electronic, thermoelectric and magnetic properties of La2NiMnO6 and La2CoMnO6

“…Their calculations designate that LNMO (001), LNMO (110), LCMO (001), and LCMO (110) should be ferromagnetic halfmetal, while LNMO (111) and LCMO (111) are ferromagnetic semiconductors with a Coulomb-enhanced band gap and a Hubbard U gap, respectively. Although the electronic structure of the compounds are readily accessible from first principles calculations, however with the advancement in experimental techniques [22,23], the electronic structure of semiconductors could also be obtained experimentally [24,25]. Shuhui Lv et al [26] calculated the electronic structure of the multifunctional La 2 CoMnO 6 at equilibrium and under strain.…”

The half-metallic ferromagnetism character in Be1−V Y (Y=Se and Te) alloys: An ab-initio study

“…Recent researches in the field of materials science [50][51][52] have demonstrated that density functional theory (DFT) provides the best means for predicting solid state properties of materials close to experimental observations [53]. In this study, we use DFT based on the all-electron FPÀ LAPWþlo method, as implemented in the WIEN2K package [54], to investigate the structural, electronic and magnetic properties of Vanadium doped BeS and BeTe with concentration (x¼ 0, 0.25, 0.50, 0.75 and 1.0).…”

First-Principles Study of the Structural, Electronic, Magnetic and Thermal Properties of the Cr Doped Ge6Mn2Te8 and Ge6Fe2Te8 Systems

“…Recently a large number of experimental studies related to the electronic structure [12][13][14], magnetism and magnetic transitions in several Ge-Te based alloys, such as Ge-Cr-Te, Ge-Mn-Te and Ge-Fe-Te have been reported [15][16][17]. In addition, there is a substantial amount of work on the DMS in general (please refer to Ref.…”