Etching characteristics of AlxGa1−xAs in (NH4)2Sx solutions

Seo, Jong Wook; Koker, Terry; Agarwala, S.; Adesida, I.

doi:10.1063/1.106461

Cited by 27 publications

(13 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Herein, we report a facile approach that uses ammonium sulfide vapor ((NH 4 ) 2 S, referred to as AS) to sulfurize the surface of the Se‐based kesterite thin films at room temperature. AS solution and AS vapor have been successfully applied to passivate the III‐V semiconductor surfaces . In fact, Xie et al have used an AS solution to remove the Sn(S,Se) phase by inserting the absorber layer into an AS solution.…”

Section: Introductionmentioning

confidence: 99%

“…AS solution and AS vapor have been successfully applied to passivate the III-V semiconductor surfaces. [11][12][13] In fact, Xie et al [14] have used an AS solution to remove the Sn(S,Se) phase by inserting the absorber layer into an AS solution. More recently, Buffi ere et al [15] passivated the surface of CIGS films by a similar AS liquid treatment.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

et al. 2018

View full text Add to dashboard Cite

The interfaces are very important for kesterite‐structured solar cells. In this study, a facile room temperature chemical sulfurization process is developed to modify the surface of the CZTSe films, which can prevent the decomposition of kesterite film at high temperature during the traditional sulfurization process and thus introducing the deep defects in the absorber layer. It is found that the (NH4)2S vapor sulfurizes the surfaces of the CZTSe thin films previously etched by ammonia. Consequently, the surface defects are passivated by the incorporated sulfur, and the interfacial band alignment is improved at the junction. The open circuit voltage (VOC) of the solar cell device is improved from 364 mV to 406 mV, with the cell efficiency increased to 9.04% when the (NH4)2S vapor treatment time is optimized at 25 min. This study affords a new perspective for enhancing the performance of kesterite‐based thin film solar cells using a facile surface sulfurization approach.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

et al. 2018

View full text Add to dashboard Cite

show abstract

“…This shows that the time of sulfur treatment is an important factor to obtain optimum device properties. On the etching and passivation process, the reaction between the (NH 4 ) 2 S chemical solution and GaAs semiconductor can be expressed as [9]:…”

Section: Resultsmentioning

confidence: 99%

Characteristics of InGaP/GaAs heterojunction bipolar transistors (HBTs) with sulfur treatments

Cheng

Liu

2006

Superlattices and Microstructures

View full text Add to dashboard Cite

“…15,16 Due to its high reduction ability hydrazine suppresses the oxidation of sulfide anions and H 2 S by dissolved oxygen. This, in turn, hinders the formation of the polysulfide anions and elemental sulfur in the solution and the appearance of these components in chemisorbed and physisorbed overlayers.…”

Section: Discussionmentioning

confidence: 99%

Wet Chemical Treatment in Hydrazine-Sulfide Solutions for Sulfide and Nitride Monomolecular Surface Films on GaAs(100)

Berkovits

Ulin

Losurdo

et al. 2005

J. Electrochem. Soc.

View full text Add to dashboard Cite

GaAs surface chemical passivation by wet chemical treatments in hydrazine-sulfide solutions with different pH values has been studied by X-ray photoelectron spectroscopy and spectroscopic ellipsometry. It is found that highly alkaline ͑pH 12͒ solutions result in a coherent monomolecular film of gallium nitride, while treatment in buffered solutions ͑pH Ͻ 8͒ yields a surface layer of gallium sulfide. Both nitride and sulfide surface films are found to be stable against oxidation in air ambient over months, attesting to the validity of the wet chemical treatment in hydrazine sulfide solutions for chemical passivation of the GaAs͑100͒ surface. The chemical mechanism for formation of the surface nitride and sulfide films is presented and discussed.In recent years, wet chemical treatments of GaAs surfaces by sodium and ammonium sulfide solutions have been investigated. 1-4 These treatments produce sulfide overlayers that provide surface chemical and electronic passivation of GaAs͑100͒ surfaces. The latter effect originates from a decrease of the surface state density in the middle of the gap, but the lifetime of the electronic passivation is too short for wide practical applications. 5 Nevertheless, GaAs͑100͒ substrates freshly treated with sodium sulfide solution can be used for the growth of molecular beam epitaxial ͑MBE͒ layers of ZnSebased structure without the growth of buffer layers as reported in Ref. 6.Recently a new wet chemical treatment of GaAs by hydrazinesulfide solutions has been reported. 7,8 The treatment results in the formation of a monolayer of gallium nitride on the GaAs͑100͒ surface. Such a layer was found to be stable against oxidation, and to yield an increase of the room temperature photoluminescence ͑PL͒ intensity. 8 In the present paper, an analysis of the surface chemistry of overlayers produced on the GaAs͑100͒ surface by wet treatments using hydrazine-sulfide solutions is presented. The impact of the pH value of the solution on the surface chemistry is discussed. It is found that depending on the pH value, the chemical treatment in hydrazine-sulfide solutions results in the formation on the GaAs͑100͒ surface of coherent monomolecular films of gallium nitride ͑GaN͒ or gallium sulfide ͑Ga-S͒ bonds, which chemically and electronically passivate the GaAs surface. A key issue for the surface passivation is the monomolecular thickness of such nitride and sulfide films, because for higher thickness the above-described overlayers lose mechanical stability due to the high value of the lattice mismatch with the GaAs substrate. Therefore, the self-limiting character of surface reactions of GaAs substrate with the hydrazinesulfide solution makes the present treatments promising for preparation of the chemically stable extra-thin crystalline surface layers. ExperimentalUndoped GaAs͑100͒ wafers with a residual impurities concentration of ϳ10 16 cm −3 were used as substrates. The GaAs substrates were degreased and etched by a H 2 SO 4 :H 2 O 2 :H 2 O = 6:1:1 solution and underwent a short ͑ϳ1 min͒ treatm...

show abstract

Etching characteristics of AlxGa1−xAs in (NH4)2Sx solutions

Cited by 27 publications

References 19 publications

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

Room‐Temperature Surface Sulfurization for High‐Performance Kesterite CZTSe Solar Cells

Characteristics of InGaP/GaAs heterojunction bipolar transistors (HBTs) with sulfur treatments

Wet Chemical Treatment in Hydrazine-Sulfide Solutions for Sulfide and Nitride Monomolecular Surface Films on GaAs(100)

Contact Info

Product

Resources

About