Use of near-surface channel conductance and differential capacitance versus potential measurements to correlate inversion layer formation with low effective surface recombination velocities at n-Si/liquid contacts

Abstract

Near-surface channel conductance measurements, differential capacitance versus potential measurements, and surface recombination velocity measurements have been performed on ͑111͒-and ͑100͒-oriented n-type Si samples in contact with nitrogen and/or liquid electrolyte solutions containing I 2 , I 2 /I Ϫ , ferrocene, or decamethylferrocene ϩ/0 in either methanol or tetrahydrofuran. Si/liquid contacts that displayed a low effective surface recombination velocity S corresponded to those that formed an inversion layer at the solid/liquid contact as indicated by channel conductance measurements or by differential capacitance versus potential measurements. Contacts that did not produce an inversion layer at the Si surface did not produce low effective S values. The observed behavior is consistent with the known energetics of Si/liquid contacts and provides an explanation for the low effective S values observed in these systems.

Modification of Surface Potential of Silicon by Organic Molecules

“…The band shift at the organic layer/silicon interface due to Qit and Qot is important for reducing surface recombination velocity. A similar phenomenon was observed in other organic materials [1,4].…”

An AFM, XPS and electrochemical study of molecular electroactive monolayers formed by wet chemistry functionalization of H-terminated Si(100) with vinylferrocene

“…A few recipes for a covalent molecular anchoring on silicon have been reported, sometimes associated with claims of a superior and long-term stability of the Si-C bond in hydrolytic conditions, which instead severely affects Si-O-R bonds [2,3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The electronic communication between silicon substrate and attached molecules has also been tested, mainly by means of electrochemical methods in a solution [4,[19][20][21][22] and, in a limited number of cases, in the solid state [23][24][25][26], and the importance of the nature of the contact has been discussed. However, it has not yet been clarified in the literature on Si-organics hybrids, if the roadmap to robust and reliable Si-based molecular electronics should select one among the existing Siorganics covalent bond already tested (mainly Si-C, Si-O, Si-P), or explore further ones.…”

A Mechanistic Study of the Oxidative Reaction of Hydrogen-Terminated Si(111) Surfaces with Liquid Methanol

“…52,18 The unique reactivity of HSi(111) surfaces with alcohols, including CH 3 OH, has been exploited as a versatile method to impart a desired functionality to the surface via the robust Si-O bond, without formation of a thick insulating silicon oxide layer on the surface. For example, n-Si/CH 3 OH junctions have yielded high open-circuit voltages (632-640 mV) and high device efficiencies (12-14%) [53][54] in regenerative photoelectrochemical cells, with the device performance correlated with low surface recombination velocities [55][56][57] as well as the favorable band-edge positions 58 of the methoxylated Si surface. The methoxy termination can moreover be converted to F-termination or OHtermination,5 double-side polished, 300 ± 25 µm thick, oriented within 0.5° of the (111) crystal plane, and had a resistivity of 0.40 Ω cm.…”