[14p-E205-1~14] 13.7 Nano structures and quantum phenomena

△ [14p-E205-7] Near-surface energy band analysis of InAs quantum dots using KFM

〇(M2)Tomohiro Kobayashi¹, Ko Takabayashi¹, Kenichi Shimomura¹, Yuwei Zhang¹, Fumihiko Yamada¹, Itaru Kamiya¹ (1.Toyota Tech. Inst)

Keywords:quantum dots, KFM, Fermi level pinning

InAs quantum dots (QDs) have been reported to exhibit size-dependent I-V characteristics, which turn ohmic-like when the diameter reaches the order of 100 nm, and has been used as nanoelectrodes for single dot tunneling current measurements. However, the mechanisms remain unrevealed. Workfunction measurements of InAs QDs has shown that dip in the workfunction (WF dip) arise at the peripheral of the QDs. WF dip suggests the possibility of the formation of electron accumulation region, thereby explaining the size dependent I-V characteristics. Previous work reported that workfunction of InAs QDs was changed by strain-relaxation and Si-doping. To elucidate the mechanisms of the size dependent I-V characteristics the workfunction of the QDs and their peripheral were investigated in this work. The results were converted into near-surface band alignment for discussing the WF dip formation mechanisms.