Surface passivation of GaAs using ArF excimer laser in a H2S gas ambient

Yoshida, N.; Chichibu, S. F.; Akane, Toshimitsu; Totsuka, Masahiro; Uji, Hiroshi; Matsumoto, Shigeyuki; Higuchi, H.

doi:10.1063/1.110250

Cited by 10 publications

(5 citation statements)

References 23 publications

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“…In the case of other III to V semiconductors, such as GaAs, laser processing in air can produce a time‐stable surface passivation . A GaAs surface cleaning by removing a low‐quality native oxide, followed by S passivation, by means of excimer laser irradiation has been also reported, showing in some cases an increase of the photoluminescence intensity …”

Section: Discussionmentioning

confidence: 98%

Strong subbandgap photoconductivity in GaP implanted with Ti

Olea

Prado

García-Hemme

et al. 2017

Progress in Photovoltaics

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Photovoltaic solar cells based on the intermediate band (IB) concept could greatly enhance the efficiency of future devices. We have analyzed the electrical and photoconductivity properties of GaP supersaturated with Ti to assess its suitability for IB solar cells. GaP:Ti was obtained by ion implantation followed by pulsed-laser melting (PLM) using an ArF excimer laser. It was found that PLM energy densities between 0.35 and 0.55 J/cm 2 produced a good recovery of the crystalline structure of GaP (both unimplanted and implanted with Ti), as evidenced by high mobility measured values (close to the reference GaP). Outside this energy density window, the PLM failed to recover the crystalline structure producing a low mobility layer that is electrically isolated from the substrate. Spectral photoconductivity measurements were performed by using the van der Pauw set up. For GaP:Ti a significant enhancement of the conductivity was observed when illuminating the sample with photon energies below 2.26 eV, suggesting that this photoconductivity is related to the presence of Ti in a concentration high enough to form an IB within the GaP bandgap. The position of the IB was estimated to be around 1.1 eV from the conduction band or the valence band of GaP, which would lead to maximum theoretical efficiencies of 25% to 35% for a selective absorption coefficients scenario and higher for an overlapping scenario.

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Section: Discussionmentioning

confidence: 98%

Strong subbandgap photoconductivity in GaP implanted with Ti

Olea

Prado

García-Hemme

et al. 2017

Progress in Photovoltaics

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“…It has been reported that irradiation of GaAs in air with 118 mJ/cm 2 XeCl and 75 mJ/cm 2 KrF lasers leads to the formation of a Ga x O y layer [12,13]. In vacuum, the efficient removal of carbon has been reported with a 53mJ/cm 2 pulse of an ArF laser irradiating GaAs, while over a thousand pulses were required to eliminate the Auger oxygen peak (originating from various surface oxides) under similar conditions of irradiation [14]. The removal of C and O from vacuum irradiated GaAs with 532 nm pulses has also been reported [15].…”

Section: Resultsmentioning

confidence: 98%

Stability of biofunctionalized GaAs surface

Ding

Dubowski

2007

SPIE Proceedings

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For a semiconductor based biosensor, functionalization of the surface and the stability of the semiconductor-biomolecule interface are the primary issues to be addressed by researchers. We have investigated a variety of strategies to passivate (001) GaAs surface with a long chain hexadecanethiol (C 16 H 33 SH: T16). GaAs substrates were cleaned and etched either with ArF excimer laser irradiation in an atmospheric environment or with conventional wet etchants. The effect of surface passivation and stability of the interface were evaluated using photoluminescence (PL) measurements. Significant cleaning of the (001) GaAs surface has been achieved with an ArF laser, as evidenced by the up to 4-fold increase of the PL signal. This compares to the 12-fold enhancement of the PL signal from samples that were alternately etched in solutions of NH 3 /H 2 O and HCl/ethanol. A combination of a diluted base and an acid possibly provides the cleanest surface and therefore the highest surface functionalization efficacy and long term stability upon thiolation.

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“…Photoassisted sulfur deposition has been examined using two S-containing precursors, H 2 S and elemental S. − Both form sulfides under photon irradiation. On GaAs(100) c(8×2), Nooney et al found that, without photon assistance, only one monolayer of S could be built up by repeated cycles of H 2 S exposure at low temperature followed by heating to 600 K. When 193 nm photons were used, thicker and unsaturable sulfide layers were produced.…”

Section: 4 Nonthermal Surface Chemistry and Film Growthmentioning

confidence: 99%

“…Auger studies indicate that As remains below the GaS x layer up to 600 K. The authors propose that GaS and GaS 2 are both involved. However, on a different surface, GaAs(001), mainly AsS was formed after ArF excimer laser irradiation in an H 2 S ambient …”

Section: 4 Nonthermal Surface Chemistry and Film Growthmentioning

confidence: 99%