赝配InGaAs/InAlAs调制掺杂异质结构的Shubnikov-de Haas振荡

SHUBNIKOV DE HAAS OSCILLATIONS IN PSEUDOMORPHIC MODULATION DOPED InGaAs/InAlAs HETEROSTRUCTURE

赝配ＩｎＧａＡｓ／ＩｎＡｌＡｓ调制掺杂异质结构可以获得很高的电子气面密度和电子迁移率，从而可以制成具有优越高频和低噪声特性的高电子迁移率晶体管（ＨＥＭＴ）．文中报道ＩｎＧａＡｓ／ＩｎＡｌＡｓ调制掺杂异质结构低温下纵向和横向磁阻随磁场强度变化的ＳｈｕｂｎｉｋｏｖｄｅＨａａｓ（ＳｄＨ）振荡和量子Ｈａｌ效应．对ＳｄＨ振荡曲线作了快速傅里叶变换，获得了二维电子气的能带结构和各能带上的电子气面密度．分析比较了顶层ＩｎＧａＡｓ不同掺杂情况对ＳｄＨ振荡的影响，结果发现顶层ＩｎＧａＡｓ重掺杂，会对表面态起屏蔽作用。

Abstract Shubnikov de Haas (SdH) oscillation and quantum Hall effect measurements on pseudomorphic InGaAs/InAlAs modulation doped heterostructure,grown by gas source molecular beam epitaxy,have been carried out to investigate the magetotransport properties of the two dimensional electron gas in the strained InGaAs quantum well.The SdH measurements at 0 3K demonstrated the existence of a quasi two dimensional electron gas in the pseudomorphic InGaAs/InAlAs heterostructure.The fast Fourier transformation results for the SdH data clearly indicate the occupation of two subbands in InGaAs strained quantum well.Comparison between SdH data on the structure with undoped InGaAs cap layer and the structure with heavily Si doped cap layer reveals that different doping in cap layer has large effect on the parallel conductance of the modulation doped structure.