Magnetotunneling spectroscopic probe of quantization due to inhomogeneous strain in a Si/SiGe vertical quantum dot

Abstract

A columnar p-Si/SiGe quantum dot is etched from a strained layer structure. The creation of the stress-free lateral face of the column results in a spatially inhomogeneous strain field within the dot which can induce lateral quantum confinement, in addition to the usual vertical confinement. As a result, a fine structure appears in the resonant tunneling current-voltage I(V) characteristics. Here we present the magnetotunneling I(V,B) characteristics in parallel magnetic field BʈI which provide an experimental probe of the hole states confined by the radially symmetric strain-induced potential in the quantum dot. The evolution of the fine structure with B reveals the influence of the magnetic confinement on the resulting one-dimensional ringlike hole subbands, which is consistent with numerical analysis of hole states of the quantum dot in magnetic field. RAPID COMMUNICATIONS R7732PRB 62 LIU, ZASLAVSKY, AKYÜ Z, PERKINS, AND FREUND 48, 15 480 ͑1993͒.

Strain-Induced Quantum Ring Hole States in a Gated Vertical Quantum Dot

“…2, which is equivalent to approximately one magnetic quantum flux enclosed by the quantum dot, while the rest of the conductance curve remains unchanged by small magnetic fields (B < 200 mT). We attribute these conductance peaks to tunneling into the quantum ring hole subbands confined by the in-plane inhomogeneous-straininduced ringlike potential near the edge of the quantum well [20], shown in Fig. 3(a) as predicted by finite element analysis [15].…”

“…The American Physical Society 096804-1 the inhomogeneous-strain-induced lateral potential in the wells [20]. When magnetotunneling measurements were performed at T 1:6 K in a weak magnetic field B parallel to the tunneling direction, we observed a periodic oscillation of a set of conductance peaks with a period of 60 mT as shown in Fig.…”

Quantum real-space transfer in a heterostructure overgrown on the cleaved edge of a superlattice

“…As a result of the cleavage of the strain-balanced SL, a cleaved edge surface is nonflat. 25,26 This nonflatness must be noticeably smoothed out as a result of the assumed secondary overgrowth on this edge surface. The nonflatness effect must be especially small for small spatial periods of the SL assumed here.…”

Quantum confinement effects in Si/Ge heterostructures with spatially ordered arrays of self-assembled quantum dots

“…Magnetotunneling spectroscopy has proven to be a very powerful and informative method for the investigation of electron [15,16] and hole [17,18] dynamics in DBRTDs. We have applied magnetic fields B up to 12 T parallel (B ) and perpendicular (B ⊥ ) to the heterointerface to resolve the strength of the confinement potential and to investigate its effect on the transport properties of our DBRTD.…”