Impact of potassium and water on the electronic properties of InN(0001) surfaces

Abstract

In this work we investigate the interaction of potassium and water with 2×2 reconstructed InN(0001) surfaces prepared by plasma‐assisted molecular beam epitaxy. The influence of adsorbate‐substrate‐interaction on surface properties is characterized in‐situ by photoelectron spectroscopy. Potassium exposure leads to a strong reduction in the work function Φ to 1.6 eV revealing a charge transfer from the adsorbate to the InN surface. In parallel, a reduction of the surface downward band bending by 0.2 eV and hence a reduced electron accumulation density is observed. While interaction of water with clean InN(0001)‐2×2 surfaces induces only minor changes in the surface band bending, water adsorption at potassium covered InN(0001) leads to a reversal of the K‐induced reduction in surface band bending and a slight increase of Φ to 2.4 eV. These results show that surrounding water modifies the interaction of potassium with InN(0001) surfaces. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

How Indium Nitride Senses Water

“…The associated core levels along with the O 1s core level (all shown in Figure along with the peak fitted data in Supporting Figure 2) remained unaffected by the X-ray beam. Charge transfer processes from the adsorbent to the substrate are consequently ruled out, in contrast to earlier studies of oxygen, potassium, and water interactions with InN. , We suggest a more universal scenario based on a model involving the spontaneous polarization of the InN film and the electric dipole of water molecules …”

“…Charge transfer processes from the adsorbent to the substrate are consequently ruled out, in contrast to earlier studies of oxygen, potassium, and water interactions with InN. 19,35 We suggest a more universal scenario based on a model involving the spontaneous polarization of the InN film and the electric dipole of water molecules. 36 In InN of N-polarity, bonds starting from the substrate are ordered from N to In.…”

“…19, 35 We suggest a more universal scenario based on a model involving the spontaneous polarization of the InN film, and the electric dipole of water molecules. 36 In InN of N-polarity, bonds starting from the substrate are ordered from N to In.…”

Synchrotron radiation photoemission study of the ultrathin Cs/InN interface

“…For the InN(0001), the surface states were found at the energies of 0.2 eV and 0.7 eV below the E F while for InN(000 À 1), (1 À 100) and (11 À 20) surfaces the surface state is located near the E VBM [26,27]. Experimental data are in good agreement with theoretical calculations for the InN surface in various orientations [13].…”

“…For III nitrides, accumulation layers were revealed at the clean InN surface [23,24] and formed via adsorption at both the GaN and AlGaN surfaces [28,29]. Adsorption of alkali metals Cs, K on the InN surface has been recently investigated in [21,26,27] in which the significant modification of the surface electronic structure has been demonstrated. For the K/InN interface, a reduction of surface accumulation and the disappearance of surface states are observed [26].…”