Formation of negative ion clusters from GeH4 has been studied as a function of germane pressure, in the 25–450 mTorr range, by chemical ionisation mass spectrometry. At the lowest pressures, only the GeHn− (n = 0–3) ion family is formed, whilst at increasing pressures GemHn− (m = 1–9) ion clusters of increasing size are observed in the mass spectra. A variable contribution of the ions with different hydrogen content is observed as a function of the pressure of germane in all the GemHn− (m = 1–9) clusters. Increasing pressures induce a general increase of ion species with a low content of hydrogen atoms. In fact, at 450 mTorr, 38% of the ion current is due to the bare Gem− (m = 2–5) clusters and 83% to the sum of abundances of the GemHn− ions without hydrogen (n = 0) and with a number of hydrogen atoms not higher than the number of germanium atoms (n = 0–m). This trend suggests that a contribution of negative clusters to the deposition of the amorphous solid a-Ge:H from gaseous systems containing GeH4, activated by radiolytic methods, can enhance the formation of solids with a low hydrogen content, which show better photoelectrical properties.

Negative ion clusters in self-condensation of GeH4

ANTONIOTTI, Paola;OPERTI, Lorenza;RABEZZANA, Roberto;VAGLIO, Gian Angelo;
2002-01-01

Abstract

Formation of negative ion clusters from GeH4 has been studied as a function of germane pressure, in the 25–450 mTorr range, by chemical ionisation mass spectrometry. At the lowest pressures, only the GeHn− (n = 0–3) ion family is formed, whilst at increasing pressures GemHn− (m = 1–9) ion clusters of increasing size are observed in the mass spectra. A variable contribution of the ions with different hydrogen content is observed as a function of the pressure of germane in all the GemHn− (m = 1–9) clusters. Increasing pressures induce a general increase of ion species with a low content of hydrogen atoms. In fact, at 450 mTorr, 38% of the ion current is due to the bare Gem− (m = 2–5) clusters and 83% to the sum of abundances of the GemHn− ions without hydrogen (n = 0) and with a number of hydrogen atoms not higher than the number of germanium atoms (n = 0–m). This trend suggests that a contribution of negative clusters to the deposition of the amorphous solid a-Ge:H from gaseous systems containing GeH4, activated by radiolytic methods, can enhance the formation of solids with a low hydrogen content, which show better photoelectrical properties.
2002
16
185
191
P. Antoniotti; L. Operti; R. Rabezzana; G.A. Vaglio; A. Guarini
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/106103
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