Abstract:By spectroscopically analyzing the light emitted from the tip-sample gap of the scanning tunneling microscope (STM), we have investigated the carrier transport as well as the luminescence properties of AlGaAs/GaAs quantum wells (QW's). The emission intensity form a target well was measured as a function of the tip position on a cleaved (110) surface of the QW structures. The thermalization length and the diffusion length of the injected electrons were determined in real space.
“…The process results in a wide spectral light distribution, which reflects the plasmonic cavity modes between the two metal contacts 9, 16, 17. STM‐induced luminescence (STL) has moreover been applied to study surfaces of inorganic bulk semiconductors 18–20 providing local information of electron–hole recombination. Within the last decade luminescence detection became a more widely applied extension to STM for the characterization of semiconductors and due to an increasing interest in the luminescence from organic substances.…”
The control of light emission on the scale of individual quantum systems, like molecules or quantum dots, is a field of intense current research. One way to induce light emission from these systems is the local charge injection through the tip of a scanning tunnelling microscope (STM). Studies which employ this method have to address one basic question: Does the detected luminescence provide information precisely from the molecule into which charge is injected by the STM tip apex or are the luminescence properties determined by a larger volume?In this article, we focus on the investigation of organic nanocrystals and discuss the relation between the local excitation, the intermolecular coupling and the influence of the STM as a measuring instrument. Choosing pentacene as an organic emitter, we present results, which suggest that the STMinduced luminescence cannot be attributed simply to the emission by a single molecule. We discuss how information about locality can be obtained and comment on the present experimental limitations and possible future improvements.
“…The process results in a wide spectral light distribution, which reflects the plasmonic cavity modes between the two metal contacts 9, 16, 17. STM‐induced luminescence (STL) has moreover been applied to study surfaces of inorganic bulk semiconductors 18–20 providing local information of electron–hole recombination. Within the last decade luminescence detection became a more widely applied extension to STM for the characterization of semiconductors and due to an increasing interest in the luminescence from organic substances.…”
The control of light emission on the scale of individual quantum systems, like molecules or quantum dots, is a field of intense current research. One way to induce light emission from these systems is the local charge injection through the tip of a scanning tunnelling microscope (STM). Studies which employ this method have to address one basic question: Does the detected luminescence provide information precisely from the molecule into which charge is injected by the STM tip apex or are the luminescence properties determined by a larger volume?In this article, we focus on the investigation of organic nanocrystals and discuss the relation between the local excitation, the intermolecular coupling and the influence of the STM as a measuring instrument. Choosing pentacene as an organic emitter, we present results, which suggest that the STMinduced luminescence cannot be attributed simply to the emission by a single molecule. We discuss how information about locality can be obtained and comment on the present experimental limitations and possible future improvements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.