Surface photovoltage spectroscopy of real 〈111〉 GaP surfaces

Abstract

Surface photovoltage spectroscopy measurements are reported for real np, n, and p-type GaP surfaces. Surface energy states are detected within and greater than the energy gap. Changing the surface condition by etching produces changes in the distributions of the surface states prior to etching, this is attributed to the effect of the adsorbed oxygen a t the surface and to changes of the number of disordered Ga and P atoms by etching.Oberflachenphotospannungsspektroskopieuntersuchungen werden an realen np-, n-und p-leitenden Gap-Oberflachen durchgefuhrt. Oberflachenzustande mit Energien innerhalh der Energielucke wid groBer werden nachgewiesen. Eine Bnderung der Oberflachenbedingungen mittels Atzen ruft Anderungen in der Verteilung der Oberflachenzustande gegeniiber der vor der Atzung hervor und wird dem EinfluB von adsorbiertem Sauerstoff an der Oberflache und Anderungen der Anzahl der fehlgeordneten Ga-und P-Atome durch das Atzen zugeschrieben.

Surface Potential Investigations of Indium Phosphate Real Surfaces by Means of Transverse Acoustoelectric Method

“…In such cases the surface parameters are determined with a very low accuracy. The similar situations are observed for all electrical semiconductor investigation methods [22,23].…”

Surface photovoltage phenomena: theory, experiment, and applications

“…Some authors have interpreted super-bandgap structure in terms of surface states found in the energy range of an allowed band [297,298,303,384]. As demonstrated in Fig.…”

“…Another venue in which SPS is frequently used is the evaluation of the effect of various treatments, such as electron [101] or ion [349,352] bombardment, etching [352,354], annealing [383,384], lightsoaking [304,306], etc., on semiconductor surfaces. Brillson [363,364,372,373,375,376] has pioneered the use of SPS in tandem with chemical analytical tools in order to assess the impact of surface chemistry on surface electronic properties.…”

“…Since the photosaturation approach is relatively easy to implement and very simple to interpret, many other studies have utilized it for determining V 0 s values at various semiconductor surfaces. These studies include further investigations of oxygen adsorption/desorption at CdS surfaces [557]; CdS/insulator interfaces [558]; a-Se/organic polymer interfaces [559]; Ambient effects on GaAs(111) surfaces [560± 562]; Effects of different etching reagents on (100) InP surfaces [563]; Effect of organic molecule adsorption on various semiconductors [50±57]; Temperature-dependence of the surface potential in Si [564,565], Ge [567,568], GaAs [569] and SiC [570]; Laser-induced modi®cation of the Si/SiO 2 interface [565]; Band-diagrams of Cd-based II±VI semiconductors [571]; Band-diagrams of various clean [11,289] and real [572±574] Si surfaces; Band-diagrams of a-Si:H surfaces [303,575±577]; Banddiagrams of organic semiconductors [412±414]; and band-diagrams of Ge [573], CdTe [384], CdMnTe [393], and NiO [578] surfaces. In addition, Brillson et al have used the photosaturation technique extensively for characterizing the in¯uence of metallic overlayers on the band bending at CdS [372,373,579,580], GaAs [579,581,582], and ZnO [583] surfaces.…”

“…A saturation of the resulting SPV f I curve at the highest illumination intensities is taken as evidence of¯at bands (hence the name photosaturation). The source of the controversy is that examinations of the SPV f I curves have produced mixed results: In some studies photosaturation was consistently obtained (see, e.g., [303,384,557,563,572,573,576,602]), whereas in others it was consistently not obtained (see, e.g., [214,607±610]). …”