Band bending at the surfaces of In-rich InGaN alloys

Abstract

The band bending and carrier concentration profiles as a function of depth below the surface for oxidized InxGa1-xN alloys with a composition range of 0.39 <= x <= 1.00 are investigated using x-ray photoelectron, infrared reflection, and optical absorption spectroscopies, and solutions of Poisson's equation within a modified Thomas-Fermi approximation. All of these InGaN samples exhibit downward band bending ranging from 0.19 to 0.66 eV and a high surface sheet charge density ranging from 5.0 x 10(12) to 1.5 x 10(13) cm(-2). The downward band bending is more pronounced in the most In-rich InGaN samples, resulting in larger near-surface electron concentrations. c 2008 American Institute of Physics. [DOI: 10.1063/1.3033373]\u

Structural, electrical and optical characterization of MOCVD grown In-rich InGaN layers

“…The existence of electron accumulation is due to the fact that the E sF is located in the conduction band below the charge neutrality layer, making electrical characterization of these materials very challenging [21]. Constant-field Hall effect measurements are influenced by parallel conduction owing to the high carrier concentration at the interface and in the surface space charge region.…”

Electrocatalytic oxidation enhancement at the surface of InGaN films and nanostructures grown directly on Si(111)

“…This matches with the symmetric CV curve for sample M2, i.e., quasi-reversible oxidation and reduction more like for metallic electrodes: The p + SD decreases with decreasing In content. Below around 40% In content the surface states move from the conduction band into the bandgap and, hence, change from donor-like to acceptor-like, causing a transition from electron accumulation to electron depletion [16]. Therefore, M2 is a common highlydoped n-type semiconductor behaving similar to metals.…”

Stable passivation of InN surface electron accumulation with sulphur treatment

“…It has been observed that InN exhibits a very strong downward band bending, up to 0.7 eV, and high surface sheet charge density of 1 − 2 × 10 13 cm −2 [3][4][5]. InN has the smallest electron effective mass, the largest mobility and highest peak and saturation velocities of the group IIInitrides and therefore, coupled with GaN, it has the potential to produce a variety of novel device applications, including radiation hard, high efficiency multi-junction solar cells [6,7], multi-colour detectors, high-brightness multicolour light emitting and laser diodes [8,9], quantum cryptography [10], and high electron mobility transistors [11].…”

“…XPS was performed at room temperature using a monochromated Al K α X-ray source and electron analyser, which have been described elsewhere [5].…”