Experimental demonstration of hot-carrier photo-current in an InGaAs quantum well solar cell

Abstract

An unambiguous observation of hot-carrier photocurrent from an InGaAs single quantum well solar cell is reported. Simultaneous photo-current and photoluminescence measurements were performed for incident power density 0.04–3 kW cm−2, lattice temperature 10 K, and forward bias 1.2 V. An order of magnitude photocurrent increase was observed for non-equilibrium hot-carrier temperatures >35 K. This photocurrent activation temperature is consistent with that of equilibrium carriers in a lattice at elevated temperature. The observed hot-carrier photo-current is extracted from the well over an energy selective GaAs barrier, thus integrating two essential components of a hot-carrier solar cell: a hot-carrier absorber and an energy selective contact.

Two-step photon up-conversion solar cells

“…Below-bandgap photons with energy smaller than the bandgap of SC are not absorbed and do not contribute to create carriers. Many efforts have been made to realize high-efficiency SCs by breaking the conversion limit and several concepts have been proposed to improve the efficiency3456789. One promising SC is the intermediate-band SC (IBSC) containing an additional parallel diode connection, which can reduce the transmission loss56.…”

Evidence of hot carriers at elevated temperatures in InAs/AlAs0.84Sb0.16quantum wells

“…Here, we propose this localization is related to alloy fluctuations at the QW/barrier interface, which is known to be problematic in these systems, particularly when narrow QWs are produced [15]. To investigate the presence of hot carriers in these QWs we used analysis proposed in several recent papers [2][3][4] where a Boltzmann-like hot carrier temperature can be extracted from the high-energy tail of the PL [16]. Above a critical power, hot carriers become prevalent resulting in a high energy broadening of the PL with increasing power.…”

“…Recently, there has been renewed interest in the investigation of hot carriers in semiconductor quantum wells (QW) [1][2][3][4]. Theoretically it has been predicted that if such high-energy carriers can be harnessed prior to thermalization, solar cells operating well above the Shockley-Quiesser limit are possible [5][6][7].…”

Hot-carrier effects in type II heterostructures

“…Primitive HCSC functionality has been demonstrated in devices which integrate these contacts with HC absorbers [6][7][8]. Nanostructured materials have also been proposed as hot-carrier absorber candidates.…”