LOW-TEMPERATURE LUMINESCENCE DUE TO MINORITY-CARRIER INJECTION FROM THE SCANNING TUNNELING MICROSCOPE TIP

Besides its conventional use in the current-imaging mode, the scanning tunneling microscope (STM) offers the possibility of studying other phenomena related to minority-carrier injection in semiconductors. In this paper we present the observation of low-temperature spectrally resolved radiative recombination resulting from the minority-carrier injection from the STM metal tip. We have studied electron injection from the Pt-Rh tip (on virtual ground potential) into the conduction band of the positively biased cleaved p-type (Zn-doped) InP. This mode of recombination is in direct analogy to minority-carrier-injection luminescence in the past employed using MIS contacts. We denote this process scanning tunneling luminescence (STL). We report on the voltage dependence of the luminescence, spatial variation of the spectra and compare STL spectra with the corresponding photoluminescence spectra.