Output power of a double tunneling-injection quantum dot laser

Abstract

We develop a comprehensive theoretical model for a double tunneling-injection (DTI) quantum dot (QD) laser. Both electrons and holes are injected into QDs by tunneling from two separate quantum wells (QWs). Ideally, out-tunneling of each type of carriers from QDs into the opposite-to-injection-side QW should be completely blocked; as a result, the parasitic electron-hole recombination outside QDs will be suppressed and the light-current characteristic (LCC) of a laser will be strictly linear. To scrutinize the potential of a DTI QD laser for high-power operation and the robustness of an actual device, our model includes out-tunneling leakage of carriers from QDs. We complement our calculations by an analytical model and derive closed-form expressions for the LCC and carrier population across the layered structure. We show that, even in the presence of out-tunneling leakage, the flux of parasitic recombination outside QDs remains restricted with increasing injection current. As a consequence, the LCC exhibits a remarkable feature distinguishing the DTI QD laser from other types of injection lasers--it becomes increasingly linear and the slope efficiency grows closer to unity at high injection currents. The linearity is due to the fact that the current paths connecting the opposite sides of the structure lie entirely within the QDs--in view of the three-dimensional confinement in QDs, the out-tunneling fluxes of carriers from dots are limited.

Theory of photovoltaic characteristics of semiconductor quantum dot solar cells

“…If we assume that the carrier exchange between QDs and the i-region is instantaneous (i.e., the carrier capture cross-sections r n,p ¼ 1 and the tunneling escape of confined carriers to the i-region is instantaneous 36 ), the quasiequilibrium will be established, the output voltage will be given as V ¼ E QD g þ l n þ l p , and Eq. (34) can be rewritten as…”

Optical power of semiconductor lasers with a low-dimensional active region

“…It is the capture velocity (measured in cm=s), which is a proper parameter describing the carrier capture into a QW. [6][7][8][9][10][11][14][15][16] The thermal escape time and the capture velocity are related to each other (see Ref. 16 for the general expression relating s n;p;esc and v n;p; capt;0 ).…”

“…1,2 Among them is the carrier capture from a bulk reservoir region [optical confinement layer (OCL)] into a low-dimensional active region. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Analytical models can provide insights into these processes and be used to optimize the laser structures to achieve desired operating characteristics. To develop analytical approaches, certain assumptions and simplifications should be made.…”

Electronic Structure Calculations of InP-Based Coupled Quantum Dot-Quantum Well Structures

“…Figure 1 depicts a typical tunnel injection structure (TIS) -an additional QW is connected with a QD layer through a thin barrier and serves as a carrier reservoir/injector for the QDs layer [6]. Various InAs/InGaAs/InGaAlAs/InP material systems [7] have been already considered for TIS and even further modifications have been proposed [8].…”