The event of photovoltaic (PV) applied sciences has progressed considerably over the previous twenty years because of appreciable developments in photo voltaic cell gadget engineering and materials science. *
As a consequence, photo voltaic cells have was advanced buildings containing quite a few layers and interfaces. The potential to conduct native investigations on the nanoscale stage that present data on {the electrical} properties of supplies and alongside bodily interfaces is turning into essential for photo voltaic photovoltaic gadget effectivity enchancment. *
The potential to conduct native investigations on the nanoscale stage that present data on {the electrical} properties of supplies and alongside bodily interfaces is turning into essential for photo voltaic photovoltaic gadget effectivity enchancment. *
Multilayer III–V-based photo voltaic cells are advanced units consisting of many layers and interfaces. *
The research and the comprehension of the mechanisms that happen on the interfaces is essential for effectivity enchancment. *
Electrical measurements based mostly on scanning probe microscopy (SPM) enable for the evaluation of two-dimensional (2D) options on the floor and alongside a bodily cross part of nanoscale semiconductor buildings. *
Among the many extensive number of SPM methods obtainable, Kelvin probe pressure microscopy (KPFM) is an software of the atomic pressure microscope (AFM) for the analysis of the floor potential with nanometric decision. KPFM is a invaluable investigative method for the research of labor features through the measurement of the contact potential distinction VCPD, that’s, the distinction between the electrostatic potential on the floor of the investigated construction and that of the KPFM probe. *
Within the article “Cross-sectional Kelvin probe pressure microscopy on III–V epitaxial multilayer stacks: challenges and views” Mattia da Lisca, José Alvarez, James P. Connolly, Nicolas Vaissiere, Karim Mekhazni, Jean Decobert and Jean-Paul Kleider apply frequency-modulated Kelvin probe pressure microscopy (FM-KPFM) below ambient circumstances to research the potential of this system for the evaluation of an InP/GaInAs(P) multilayer stack. *
KPFM reveals a robust dependence on the native doping focus, permitting for the detection of the floor potential of layers with a decision as little as 20 nm. *
The evaluation of the floor potential allowed for the identification of house cost areas and, thus, the presence of a number of junctions alongside the stack. Moreover, a distinction enhancement within the floor potential picture was noticed when KPFM was carried out below illumination, which is analysed when it comes to the discount of floor band bending induced by floor defects by photogenerated provider distributions. The evaluation of the KPFM knowledge was assisted by the use of theoretical modelling simulating the vitality bands profile and KPFM measurements. *
KPFM was carried out utilizing a scanning probe microscopy system below ambient circumstances and operated within the frequency-modulated KPFM (FM-KPFM) mode utilizing a two-pass scanning mode, the place the second cross was carried out at a continuing distance of 10 nm from the pattern floor. *
The FM-KPFM mode was chosen over the amplitude-modulation mode (AM-KPFM) since it’s well-known that it supplies higher spatial decision. Specifically, in AM-KPFM {the electrical} pressure between the tip and the pattern is instantly evaluated, whereas in FM-KPFM the gradient of the pressure is analysed. Because of this, FM-KPFM is extra delicate to native tip apex–pattern floor interactions; due to this fact, long-range electrostatic interactions of the cantilever are decreased, in addition to the impact of parasitic capacitances. Moreover, in FM-KPFM, floor potential measurements are much less depending on the lift-height tip–pattern distance than in AM-KPFM since this mode is much less delicate to static offsets induced by capacitive coupling or crosstalk. *
The laser beam deflection system within the creator’s AFM employs a laser wavelength of 1310 nm, which is properly under the bandgap of the pattern; due to this fact, the parasitic laser absorption, which can intervene with the KPFM measurement, is decreased to negligible ranges. Extremely doped NanoWorld n+-Si ARROW-EFM suggestions (typical AFM tip radius < 25 nm) with a conductive Pt/Ir coating at a typical resonance frequency of 75 kHz had been used. *
KPFM measurement below ambient circumstances on the floor cross part of the pattern below illumination: (a) topography and (b) VCPD picture. A vertical colored bar is included to ease the identification of the totally different layers. The profile in (c) corresponds to the area recognized by the dotted white segments in (b), every level of the profile (vertical) path being a median of 207 factors over a width of 0.7 μm alongside the x axis. A number of areas alongside the construction have been highlighted utilizing totally different colors (see textual content). The black arrow signifies the house cost area on the InP:nid/InP:Zn interface.
*Mattia da Lisca, José Alvarez, James P. Connolly, Nicolas Vaissiere, Karim Mekhazni, Jean Decobert and Jean-Paul Kleider
Cross-sectional Kelvin probe pressure microscopy on III–V epitaxial multilayer stacks: challenges and views
Beilstein Journal of Nanotechnology 2023, 14, 725–737
DOI: https://doi.org/10.3762/bjnano.14.59
The article “Cross-sectional Kelvin probe pressure microscopy on III–V epitaxial multilayer stacks: challenges and views” by Mattia da Lisca, José Alvarez, James P. Connolly, Nicolas Vaissiere, Karim Mekhazni, Jean Decobert and Jean-Paul Kleider is licensed below a Artistic Commons Attribution 4.0 Worldwide License, which allows use, sharing, adaptation, distribution and replica in any medium or format, so long as you give acceptable credit score to the unique creator(s) and the supply, present a hyperlink to the Artistic Commons license, and point out if modifications had been made. The pictures or different third-party materials on this article are included within the article’s Artistic Commons license, until indicated in any other case in a credit score line to the fabric. If materials isn’t included within the article’s Artistic Commons license and your meant use isn’t permitted by statutory regulation or exceeds the permitted use, you have to to acquire permission instantly from the copyright holder. To view a duplicate of this license, go to https://creativecommons.org/licenses/by/4.0/.